Hi and welcome to the forum.

Most new pc's can handle editing ok, however you should try to get the fastest cpu you can afford as video editing is probably the most cpu intensive task you can ask of your pc.

Secondly 2gb or more of ram is nice, 1gb would be the absolute minimum really.
And 2 or more hard drives, one as a system drive with the os and your software and a second for your video footage ( bigger the better and should be fast 7200rpm or more with a large cache)

Graphics cards aren't that important as most NLE's don't use them much

Firewire card is essential for transferring video from your camcorder to the pc, don't capture using USB as the quality will suffer.

Those are probably the main points but if you have a look at the other threads in this section you'll see some of the pc's people have built for the task.