Normally, Apple's documentation on the main beta release page (also behind the paid developer wall) lists only those differences between the last major firmware version (currently 3.2) and the newest beta (currently 4.0 beta 2). Over the last few days, I've been able to point quite a few people over to the document that shows the differences the previous beta (4.0 beta 1) and the current (4.0 beta 2). By checking in there, you can easily see what's new right away when a beta build drops. Hopefully this will save some of you a bit of extra work.
Thanks, Emanuele Vulcano!