Pretty sure that Windows Movie Maker (free with XP) will do the job, and it's fairly easy to use. Be warned, save often as video editing is a very processor-intensive task and may well lock up/crash your machine (unless you have a cutting-edge super-spec jobbie).
VirtualDub (free download) will also do the job, but is a lot more basic. Watch out for the settings, as it can create HUGE files if not properly set up.
More info than i could possibly give you here:
http://www.videohelp.com/ but feel free to post if you have any more specific questions.
P.S. re-reading your Q, VDub is probably the easiest way to simply split the footage into 2 or 3 parts. I do have another AVI splitter at home, but can't remember what it's called.