I love Google Talk because it’s simple and clean, but unfortunately that’s not the same with Yahoo Messenger. Bright colors and unwanted features make Yahoo Messenger look ugly! Thankfully, someone has created Google Talk skin for Yahoo Messenger.
Installing the skin:

* Download the skin from here
* Extract the contents of the zip and move it to C:\Program Files\Yahoo!\Shared\Graphics (default installation folder, change it only if you have installed Yahoo Messenger somewhere else)

Activating the skin:

* Run Yahoo Messenger
* Go to Messenger > Change skin…
* Choose Google Talk from the drop down menu and click OK