DowDawg is spot on, I did this to move 1000+ members to dolphin, I was a bit worried as it was the first time that I had attempted anything of that scale and I did mess up a few times, but it was ok cos I made a copy database first so that I wouldn't be messing with the original, it took a while (couple of days) but I learned alot doing it. So if you wanna learn, have a go yourself.