you really don't want to get a laptop just for editing, but there are some things that you should keep in mind when you are browsing for laptops.
cpu: dual core = good. it might be a little hotter and kill battery life, but you will want that power for editing. if you are going to choose a single core machine I'd go with a AMD Turion processor (2Ghz if you can, but kinda get whatever you can)
ram: one area you really don't want to skimp on. for video editing, 1GB is good. Anything lower than that and you're pushing it. I made a few amvs with my laptop and 512MB of ram, but started getting memory access violations and decided to upgrade to 1GB.
2GB is great, about the most memory you can see in a laptop
you shouldn't worry about ddr and ddr2. whichever you get.
Hard drive: you want big, but you can get by with a small(er) drive. I'm working on my 80GB drive (made a few amvs with only my notebook's internal), but I do have 2 120GB external drives. comes in handy for storing lossless clips. The minimum you probably would want is 60GB
other: usb ports are useful, look for about 3 or 4 on a laptop (you can buy a usb hub if you need more)
dvd drive is a must. you only need a drive, not a burner (though it can be useful)
super multi is the way to go if you want a burner (it can read/write all dvd disks)
I'd suggest winXP. Besdies compatibility, XP uses less system resources (which would probably otherwise be used by your editing program(s) )
given that, some suggestions:
http://www.newegg.com/Product/ProductLi ... 1041006877
for the record, I have had good experience with my compaq presario laptop. No problems so far. I got lucky and have seperate v-ram (so it doesn't take any of the 1GB I have installed)