Past life regression is the re-experiencing of a previous lifetime.There are many ways you can do this.Some people will go to a psychic,some to a spiritually-oriented clinical psychologist who use many different methods.
Some of the methods they use are Gestalt Therapy, Dreamwork, Visionary Journeys (including Past-Life Therapy), and Hypnosis.
If you've ever heard a song,seen a picture or experienced something that for some unknown reason jogs some kind of memory in you that is just off the wall and isn't something you remember doing/experienced in your past(as in this lifetime),but it's a memory that is so strong and familiar to you anyway that could very well be a memory of a past life.Every once in awhile I'll have a memory pop into my head like this.It's a bit suprising at first,at least to me it is.But I've kinda gotten used to it as I learn more about myself.
I hope I'm making sense here.This is one of those times I wish I could just send my thoughts to the computer screen so they would come out right lol.