I dropped from PR5 to PR4 to PR1 when I moved from a subdomain to doamin. The funny thing is that I actually worked hard on the domain name and SEOd it and everything.
I moved from freewebsite.5u.com to pgtutor.com. I guess it's too late to learn about 301 redirects now- whatever they are.
Javascript <% response.setStatus(301); response.setHeader( "Location", "URLHERE" ); response.setHeader( "Connection", "close" ); %> Code (markup): It's the most search engine friendly way of redirecting... don't worry too much about PR... It's not the most important thing... Having good marketing and people will come regardless of PR ^_^