actually photoshop doesn't need the super duper video card. Once you have a moderate video card the real photoshop stuff is needing a powerful processor, ram, fast hard drive, and preferrably a scratch disk on another hard disk. But, unlike say, 3d modeling/animating a high powered graphics card isn't the numero uno thing ya need. Of course, I do both so I do want a big phatty video card if I can get one
Having said that, he really does need to give us more info. Which OS, what programs, how big are the files, portability, other uses, etc etc.
EDIT: ok, pc, well for video you need a 5400rpm at a very minimum, but look to get the 7200rpm hard drive. I'd also say 1 gig, maybe more depending on what kinda video work your doing and also how big your photoshop files are, or plan on being (ie is this print work, just for yourself, for 3d animation, for web, etc). I like the Pentium M, but that is assuming you are going to be working from a battery. If not, then well, a p4 with the Hyperthreading is nice, but they are horrific for batter life. Also an amd64 might be good although I truthfully don't know how they fair in photoshop, although I'd imagine well. I'd also recommend going with at least wsxga or higher resolution to have more "room" to work on those files.