I feel pretty ambiguous about it, but it's an interesting idea. My mom is pretty much a believer, partly because of bizarre things I said when I was really little (three years old?) about my mom and dad being farmers and losing their armour or some other strangeness completely unrecognizable to anyone.
I've also wondered about it because certain old buildings I go into have given me really crazy deja vu and sometimes very bad feelings, like I remember something bad happening there. One time it was so unsettling I had to leave a building and almost threw up outside. Maybe I'm just crazy though.
There are a lot of logical, rational, unextraordinary explanations for the stuff that comes out of past life regression therapy, deja vu, etc. so I don't know that I "believe" in past lives and/or psychic phenomena, but I can't rule that stuff out completely because it's just too much fun to think about!