Windows XP/Vista dual boot.

Hello, im working on this emachine C3060, and it is slow. 512MB ram, 160gb hss (5400rmp -) AMD Sempron Processor 3000+. Well they wanted Vista on this machine, since it could be temporary im going to have it dual boot with vista on activating trial. Although Vista boot and things are weird and different than XP, i donno what to do. I would think its best to have another HDD, but i don't want to put one on this machine. 2 OS on the HDD, i think will give it problems especially if vista needs to be uninstalled. So im thinking of partition the harddrive into 3 partitions, 1 for emachine recovery, one xp, one vista. Whats the best option that you think.

What is a good program that I could use to partition this drive?
How does AMD Sepron Processor 3000+ 2.0GHz compare to a intel P4 3GHz?

Thanks.

Edit: just partitioned my drive and installed it that way. Also found a really good guide, even though i didn't use it.