Holder for Fahhem's plugins and possibly patches for the Pidgin/Finch/libpurple community. Keep checking back (bookmark me!) for updates.
November 2010 Update: I have moved on since early 2009, patches are welcome but I'm not actively developing this. Best Regards, Fahrzin Hemmati.
This plugin enables the long-awaited Invisible status for Google Talk users (works for Finch, Adium-X, and other implementations of libpurple as well). According to the ticket, this will never be implemented in the source code itself.
The source C-file is included in the above zip-file. If you don't know how to use it, the CHowTo page is a great place to start. Feel free to add the GList calls to add multiple account support.
To install, download and extract the zip file. Move the .dll file (or the one with gears in the icon if you can't see extensions) to "C:\Program Files\Pidgin\plugins\". Restart Pidgin and enable it (Tools->Plugins).
To install, download and extract the tar.gz file. Move the gtalkinvisible.so file to ~/.purple/plugins and restart Pidgin.
To install, download and extract the tar.gz file. Move the gtalkinvisible_64.so file to ~/.purple/plugins and restart Pidgin. Make sure you're running a 64-bit OS and 64-bit Pidgin or use the 32-bit version.
There is a blog post where you can submit bugs and comment. I hope this plugin helps!