Gaim 2.0.0beta6 was released a couple of days ago. People using Feisty the fawn are already able to get it from the official ubuntu repository.
If you are running Edgy Eft, you can get the latest release of gaim as a .deb from Debuntu .deb repository.
This new package actually includes support for NetworkManager through DBus. This feature was introduce in gaim 2.0.0beta4.
Here is the description of this feature (citing Sean Egan):
Another application that lives in the “system tray,” even when it doesn’t have any urgent notifications, is NetworkManager. NetworkManager is a really cool system that makes connecting to various networks on Linux really, really easy. It also provides a way for an application to be informed when the network status changes: when a cable is unplugged, when you connect to a wireless networ, etc.
Thanks to work by Paul Betts, Gaim can now talk to NetworkManager when connecting to IM services. Before it logs in, it will make sure you’re connected to the network and, if not, connect you as soon as the network comes available. When the network goes away, Gaim will disconnect; when it comes back, it will reconnect.
If you use a lot of plugins which are not yet post gaim 2.0.0beta4 API compliant, chances are that your plugins won’t work anymore.