I'm running an underground electrical service (240 volt) from the meter to the house, 250 feet. What would the wire size be and the size of the conduit? The main panel will be 200 amps. I would like to get a price for both aluminum and copper.
Thanks

You don't necessarily have to use conduit, but it needs to be put deeper, like 36". The utility governs these regulations and they may require their own wire or may require that they burry it.

At least 250 kCmil for 2.2% voltage drop with a #4 grounding conductor for copper.

At least 350 kCmil for a 2.5% voltage drop for aluminum with a #2 grounding conductor.

Wire type may modify these a bit. Wire type influences conduit sie.

Here is an example for a utility's require,ents.

http://www.nipsco.nisource.com/elecstd/er/er19270.pdf

Services are sized differently the branch circuits. We do not use the same method for figuring voltage drop for both.
For instance, we would not use 200A if we needed to figure voltage drop for a 200A service.

Also, service conductors are sized smaller that typical branch circuits.

The utility in my area would recommend "standard" sized cable for up to 250'. Beyond that they would recommend up sizing.

For up to 250' I would use 2" PVC, and 4/0, 4/0, 2/0 AL conductors, or 2/0, 2/0, 1/0 CU conductors.
Beyond that I would bump up to 250mcm AL.

Let me give you another option. Could I run an underground service (220 volt) from the utility pole at the roadway to a cabin about 600 feet away, instead of the utility company running overhead wires halfway or is that to big of a run. I wanted to put in a 200 amp circuit panel, however the needs of the cabin doesn't require that big of panel. I was looking at running 400 kcmil in conduit. Also would that wire be possible to pull by hand?

400 MCM would do the trick.

Many hands would be needed to pull this run.

More than likely will need a truck or a wire puller to pull this.

Be sure to use steel elbows if your using PVC conduit. PVC sweeps will melt from the friction of pulling long runs.

Do yourself a favor and use min 4 inch conduit.