If you are running SIM-IM under Mac OS X, links are not clickable - or they are in fact hyperlinks, but they cannot be executed.

Go into Setup and choose the Plugin "Navigate". Enable it, and enter the command open /Applications/Camino.app into the "Browser" field. Of course you can use any other installed application than Camino, like Safari, Opera or Firefox.

Do likewise for the "Mailer", I use open /Applications/Thunderbird.app mailto:%s.

To start any Application bundle from Terminal, type