A-Patch for Yahoo! Messenger allows you to remove the advertisements displayed in the Yahoo MEssenger and also run several istances of the application at the same time.
Also, it doesn't actually patch Yahoo, all it does is add some registry entries which disable the ads and enable multi-messenger for Yahoo Messenger!
A-Patch for Yahoo! Messenger will remove Contact List advertisement and the Chat Room one. A-Patch for Yahoo Messenger does all that with a single click.
Download A-Patch for Yahoo! Messenger