Its the best windows thus far IMO. Uh yeah there are plenty of rips of XP out there, even some like 9 in one cds with pro, home, media center edition, etc. on one CD (not DVD). At least thats my favorite, its rather hard to find now, but the release group is called XISO.
Anyway cleaning wise, I defrag once a month, use crap cleaner for other stuff. Also I used to use a program called registry mechanic, it works wonders.