How do you go about registering it with a developer?
Basically find someone who has a developer account. I happened to find a developer on FM forums who was willing to register UDIDs for free. Be aware that using the beta software will break some apps. When I was on beta 1 of iOS 5 no streaming apps like Netflix and Hulu would work. Now that I am on beta 4 though they are working fine. OTA (WiFi) sync and updates are working now too, which is a huge plus.