im completly new to all of this, and most of this info on here is totaly over my head. What im looking to do is convert my office into a gaming room as well.. this will be used 98% with an xbox360, so here are my questions:
Mainly, i have 10' distance to mount the projector from the screen.. how big of a picture will this give me, i'll be sitting about 7-8' from the screen if that matters.

Second, im wanting to keep this super low budget, preferably under $1000 and think i might have found a good deal on a dell projector (i own 6 dells and have had great luck with everything) but here are the specs:
720p DLP projector
2000 ANSI lumens
2100:1 contrast
800x600 (native) / 1400x1050 (compressed)
4:3 native apsect ratio
24-bit color support

dunno how much of that is even relavent, but there ya have it.. i'd like to make some type of homemade screen that could be taken down if needed.. like i said earlier, im looking to keep this low budget (to keep the wifey off my back) and not looking for anything super duper high tech, just somthing with a good pic.. preferably as good as my samsung rear-projection 50" 720p i'm use to watching.. thanks

Welcome to the forums, randomhero47.

What model is that Dell PJ? If it's 800X600 native, then it can display 720p/1080i pics, but it's a SVGA PJ. Make sure it's rated well for home theater use, because business PJs typically are too bright and don't display colors as realistically as a home theater type PJ. You might want to spend just a little bit more and get a H70 or H1000 (look around in the PJ<3000 subforum for more reviews). Or, the IF 4805 would be another low cost alternative in your budget - that was one highly regarded 480p PJ a couple of years ago.

You can get a Model C pulldown for pretty cheap, or if you are handy, you can just buy the HP material and build your own screen.

Good luck - I'm sure others will chime in, but you'll probably get better responses from the specialists in the subforums than in this generic forum.

Be sure to post your setup - you never know who you'll be helping down the road (like some of those starving college students who want a HT setup!).