I'm sure this will be able to run it, but I was wondering if anyone could give me an idea of how well it would run it and what graphic settings i will need to set it to. 
I'm fairly new to PC gaming so any advice helps. 
 
Intel® Pentium® Dual Core™ T4500 (2.3GHz/800MHz FSB/1MB cache)  
Intel  GMA X4500HD   Graphics Card 
2GB Shared Dual Channel RAM

 
Edit: I haven't bought it yet, but the computer i'm looking at is the Inspiron 14 Laptop with these specs.  It's perfect for my price range and I can't really go above it, at the most i could add one more GB of RAM

the pentium part is a bit iffy given that that's pretty old technology by now. There are some good tools for this like can you run it. google "can you run it" and type in fallout 3 and you should get an idea

It will probably be able to run it, but only just. If you're looking to play modern games, do not get an Intel GMA graphics card. They're integrated cards that aren't designed for medium to high end gaming. You'll want a dedicated ATI or Nvidia card if you want to play games.

Hmmmm, yeah maybe you should wait a little until u can get a dedicated video card in there. It doesn't have to be really fancy but if video card has shared memory it most likely doesn't run a lot of stuff. I don't know this graphics card but the CPU should be fast enough to run Fallout3 decently and 2 or 3 GB RAM will be enough, too. 
 
If you don't necesarrily need a laptop you could buy a real computer for that money and get something faster.

Okay how about this one? 
 

 Windows 7 Home Premium 64-bit