Ummm it's not really hard just go to newegg.com get a gfg case get some gfg parts and throw em in boot it up and there you go... thats what i did took me an hour to install everything (both the hardware and the software) it's not really that hard.

Honestly if your looking for cheap head over to newegg.com good prices for good stuff great quality to there are a few other sites i know that are good as well but i forget them right now.

I'm hoping to do this over the summer.
I plan on running 24/7 if possible. A few reboots are fine.
I plan on doing a lot of gaming.
I will need a lot of ram.
I would appreciate any tutorials however what I am really looking for is where I can get reliable items for fairly cheap.
I plan on dual booting ubuntu and XP

You can get by with a 32-bit CPU, max of 4GB memory. Look for a dual core, upwards of 2.5 Ghz or more.

Memory would be DDR2 or DDR3, with a GPU for graphics.

The higher clock speed the better. You can get a 250GB hard drive for pretty cheap now a days compared to what it cost before.

How much money were you looking to spend?

I was thinking a 64 bit because i intend on running VMS so i will need a high amount of ram. this current comp is 64 bit so im use to it.
hoping to spend 200-400

Your not going to get what you want for 200-400
Lets face it people
Theres no point in upgrading to the dieing edge
You need to be updating to the leading edge.
a decent computer will run you about 800-1300
Sorry to say but your going to need more money and do a little more research

If you want to do research on what parts or "budget" computers take a look on gizmodo.com tomshardware.com and maximumpc.com has a lot of articles on 800$~ pc's

http://www.maximumpc.com/article/features/how_build_a_kickass_800_gaming_pc?page=0%2C0

As Sanny said, save up for a couple of more months and spend 800-1300 on something decent that will actually last you. 200-400 is a horrible budget for a new computer and is only fitting for upgrading, 600 not much better.