Google Talk is just getting better and better. The latest update includes Voicemail, File Transfer and Music Status.
Its not yet released in the mainstream, but you can go ahead and start using it by downloading and installing from this source.
- Voicemail
If a friend isn't around to answer your call, now you can leave a voicemail. You can even leave voicemail messages for your friends who don't use Google Talk--they'll receive an email with the message attached as an audio file.
With this top requested new feature, you can send unlimited files and folders to your friends through Google Talk. There is no restriction on the file type or size and the peer-to-peer transfer is fast and reliable.
Listening to music while on Google Talk? Now you can let your friends see what you're listening to by selecting "Show current music track" in your status menu. Your status message will change when your song does!
Now, what I need more and waiting for Google Talk to include are the conference capability, video support, and able to call landlines and mobile phones.