I wonder how we get 120V to the homes, but for the power to the house 240v to the meter, is their some type of transformer that steps down the voltage down to 240v to 120V?   

The 120 coming into your house is really 240 split in two, the neutral is the center tap on the pole transformer so between the neutral and either live you have 120 volts and between the two lives not using the neutral you have 240, and it's easier to power large loads like a stove from 240 as you need half the current for the same amount of watts so you can use thinner wire..

So the pole transformer output would look like this

120                     240
Neutral       Or
120                     240

There is no transformer after the meter to make this work..

Well I live in America, here we do get 120V.

Yes, you get 2 x 120 volt lines, if you add them together you also get 240, the neutral is just between the two lines so you can select 120 or 240 depending on the load, your stove and dryer will use the 240 and rest of the house will normally use the 120..

Think of it this way our American power comming into
Home is dual voltage and  Neutral  split the 240 volt
In half making it 2x 120 volts but it also serve to take
Unballance current back to transformer.  Without
Nuetral your home become 240 volt.  And. Both
120 Hot wires become a series circuit on 240 volts
Causing problems.

 120  L1 ———-0———-120L2
 
   L1 ————240V ———L2

Out pole transformer are just 2 x 120 volt winding stacked together.

Here how it wires let use some incandescent here

L1 —60 watt .5 amps— 0 V — 100 watrs .83 amps —2
 
The neutral takes the unballance of two  of .33 amps

With out it what will do 100 watt bulb will want .83 amps
But .5  amp 60 watt bulb goes I cant do it so it overheats
Also voltage will rise on the 60 watt bulb too. Causing 60 watt bulb to burn out, lwe be in sitution like xmas light
Around the house.  Until it sort the load out until u do
Unbalance the load on whole house.  That why we have
A center tapped Nuetral.


 

I will never understand American electrics  

Here, it's just single phase 240V for domestic customers, with 3-phase 415/240V for larger businesses etc.

Although now they are trying to tell us the voltages are now 230/400V, our supply here never drops below 245V. But then we do have a substation outside the kitchen window  

@ Ria back ib early days of american electrics
They had 240 volt center tapped transformer
On the poles. What they done took half of transformer
Winding for 1 house and the other half of winding
Of 120 volt went to other house.  About until late
1930s electrical demand grew and transformer
On pole becomeing loptsided with unballanced
Loads. So they came in at new houses at time
240/120 dual voltage. To even the electrical
Load on transformer. About 1950s when
Things got bigger due to Central A/c  and
Electric stoves coming about and electric clothes dryer.

The way they do it here is the main cable that runs down the street carries the 3 phases. Each house is fed from alternate phases, so say the phases are red, yellow and blue (which they were until some idiot in the EU decided they should be different) - house 1 gets fed from red, house 2 from yellow and house 3 from blue.

If someone needs more power for a large industrial machine or whatever, they get all three phases.

The block where I live is three floors, with 2 flats on each floor. The incoming supply is 3-phase, two flats get fed from each of the three phases.

The 2x120V/240V was started by Edison with his DC electric system.
120V was maximum he managed to safely control (light bulbs, switches, fuses, generators,...) with the DC current at low enough cost to be practical even in homes. The DC made that task rather difficult, as no zero cross means the arcs were very persistent, so more difficult to handle in the instrumets, compare to the todays AC.
For DC there were no transformers, so the same voltage must have remain from the power station till the load. So in order to reduce the losses, someone in Edisons company came with at that ti e clever idea to pair two circuits so the positive terminal of the first circuit share conductor with the negative of the second circuit. That mean together there were one positive and one negative line wire, plus one common neutral. And because the currents from the first circuit cancel out the currents from the second one inthe neutral wire, there was no voltage drop over it even when this neutral was thinner than the line wires. And so more of the drop was allowed on the line wires, allowing these to be eithervthinner,or able to reach longer distances.
So houses were wired with load between one of the line wires and neutral, so getting the 120V.
Then with conversion to AC, the same concept remained, as the houses were already wired that way, so it remained as home standard, even when it is not that practical from the mains load balancing perspective on the HV side.
Because it was so spread, it became a fixed standard, it became not that expensuve to install separate transformer for each house,so allows high voltage to be used for street feed lines. This then made the complete 3 phase power way too expensive for not homes and small businesses (threetransformers or three phase transformer would be way more expensive tha a larger single phase one), so for larger loads the system was extended later to use the 240V across the transformer secondary.

In Europe and most other parts of the world the electricity arrived way later, when the AC power wasthe common place and so the wiring standard was designed to better suit the three phase nature of the AC distribution system. There the customers generally get all three phases (except some very small ones, like one dwelling unit in an appartment house).
This was of two forms:First connect the customer loads across the phase wires (many old pre war 120V installations, in some countries used even with 230Vtill today.
And then the 3 phases plus neutral system as most common today, designed to connect small loads between one of the phases and Neutral and having complete 3 phase connection for larger or spinning type loads.
By the way using the HV feeds along the streets and poletransformers for homeconnection is not possible in Europe, because on the streets in cities no HV lines are allowed (there is quite wide building exclusion zone around any HV installation, that means no line could fit between existing buildings in most European cities), so the power distribution has to suffice with below 500VAC between wiresandbelow 300VACtowards ground. And that is the base for the 3x230/400V used today.

That's an interesting explanation, thank you 

Also in the UK there was some 3 wire DC mains in fact at one time there was a lot as well as AC with voltages between 190 and 250 volts although 230 was the most common. Here in Weymouth we had 230/400 AC as well as 230/460 DC In London there were something like 15 separate supply company's just in central London and hundreds throughout the country. Even frequencys were not standard anything between 25 and 100 cycles