You can make pretty decent AMVs with the freeware
Windows Movie Maker.
Another alternative would be using Virtualdub (rather primitive but it works).
If you are looking for a good editing software, then you should go with Adobe Premiere but it costs buck$ (and in the three digits dimension).
If you want to know more about this site and AMV making in general please refer to my (Unofficial) FAQ (link below)
You should never underestimate the predictability of stupidity.