We are in the process of updating some sites from .asp to .net, and in doing so the page names will be changing. From what I have read a 301 redirect is the best way to handle this situation. We had done this to another site of ours but in doing so we had completely lost our PR for about 5 months. Our overall trafic did not drop, but our leads did.
Is it possible that we lost PR because the new pages didn't have any historical data attached to them? I had read that another alternative is to set up a 302 redirect and then several months down the road, when the SE's have indexed the new pages to setup up a 301 redirect. Is this a good alternative? Is there any way to keep PR when page names changes?
If the new domain is really new, you'll want to do a 302 in the beginning so that you can maintain some rankings. The rankings will be of the old domain, but you'll get the traffic through the new domain because of the automatic redirection.
Continue to build out the new domain, get links, etc just as you would for any new site. Then once it has emerged from Google's aging delay switch your 302 over to a 301, realizing it's going to take 4-6 months from that point for the links pointing towards the old domain to be transferred to the new domain.