My only advice is if you want it to look good, hire out someone to do the Mudding / Taping / Sanding / Texturing. If you do not have any experience doing it, let someone that knows what they are doing do that part. Hanging drywall is easy, but everything else about it sucks! Especially sanding!
Redrocker is exactly right......
I'm currently doing mine now that i've had the entire south side of the house dug up and Rub-R-Wall installed to ensure that my Man's Lounge is not damaged in the future by water.....
Plan it out, sit down sketch out where your thinking everything is going to go....it takes a lil while to take all the dim's and transfer that into a drawing, but, it may help in laying out how you will use the space....
Currently i'm drawing my basement, i'm laying out everything to get a better understanding of where i will need telephone jacks, outlets for lamps, cleaning etc, tv outlets and how high.....a lil pre-planning will help in the process trying to think of everything on the fly always is a bad plan....
Here's some ideas on costs just for the walls:
For approx 600 sq ft you will need about 100 2X4 studs @ 24 in o.c. at about about 200 bucks.
Insulation - great for sound absorbtion during awesome Clone games - family wont hear ya swearing....7 bundles with 9 batts per bundle - 335 dollars
Drywall - 150 bucks around 30 sheets @ 5 bucks a sheet
700 to do the walls....
Now on top of this you will need screws, nails, elec. boxes, ceiling, flooring, paint, tape, mud, texture, base, lights, wiring and other misc.
the walls are cheap, its all the amenities.....