Depends which game you're going for.
Best bet is to look on
www.polycount.com - they've got all the info you'll need for getting the models into the game of your choice.
From what I can gather, models for original UT seem to be generally around 1000 - 1500 polys.
You'll need to use something like LithUnwrap to generate the base image for the texture map, or use Painter3D to paint directly onto the model. I prefer to do the skin in 2D, then wrap it around the model.
You'll also need to download the player model SDK to get the skeleton. I think it's available from the Unreal Tournament website.
I'd recommend hanging around the pimping & previews section of the Polycount message board too, as it can give you a good idea of the possible pitfalls involved (and you might pick up a few handy tricks too - I know I did!).
Link: Polycount message board (Pimping & Previews sectio