GYach-E supports Voice Chat and Webcam for Yahoo! Messenger in Linux. It can be installed in most Linux distros by compilation from source. Visit the project homepage here.
Ubutnu users can install GYach-E by simply enabling repository and installing via Synaptic Package Manager.
I recently encountered a Youtube video which featured Gnome Do with Docky. Then I dumped the Cairo Dock I was using and replaced it with Gnome Do. I have also tried kiba-dock which is quite buggy (it is in developement). I also tried the Avant Window Navigator but found it was not so good to my liking.
The Gnome Do features the Advanced indicators which mimics the OS X dock and it is totally awesome.