Cool tricks with AT codes

What you can control

XMMS

Xmms::Remote is your underdocumented friend.

Galeon

You just write bookmarklets and invoke them via system

Everything else

Well, anything you can write Perl for at least.

Check out examples/remote in the Device::Ericsson::AccessoryMenu distribution. It's the remote I'm using for this presentation, and already includes XMMS and Galeon menus.