is there a good place to do that, if so i need to start doing my homword because i have no clue what needs to go into a computer
http://Newegg.com is a great place to find parts.
http://www.tomshardware.com/ has some good tutorials and reviews and stuff. And you can always ask here http://www.gamesas.com/topic/1376885-the-community-tech-thread-no-115/
Basically in order to build the computer you need:
Tower Case
Operating System
RAM
Video Card
Processor
Motherboard
Optical Drive
Hard Drive
Power Supply Unit
And you need to make sure that they are all compatible components. (Mainly the CPU/RAM/Motherboard are the ones you need to worry about the most with that)