Today, the (hopefully) last beta in the development cycle of Gaim 2.0 has been released. There’s no specific changelog from beta 3[.1] to beta 4, but I’ve been watching the progress in nightly builds, and there have been some significant changes, including the addition of the buddy icon next to the status selector (which I’m not sure I like).
But the most important change, at least for Windows users, is that as of beta 4, Gaim now works with newer versions of Gtk+, fixing a longstanding bug that made running Gtk+ 2.8.x (required for development versions of The Gimp) and Gaim simultaneously impossible.
Gaim 2.0’s been stable for a long time, so I suggest you upgrade. It takes some getting used to, but it really is a nicer program overall. Get it here for your platform. Windows users, you can get an installer for Gtk+ 2.8.18 at the Gimp for Windows page.