Those of you Apple folk probably know that the latest Powerbooks have a trackpad that interprets two finger movements as scrolling instead of mouse movement. Well, someone has been kind enough to put together a mouse driver implements that functionality for older Apple portables as well as adding a shortcut for contextual clicking. You can find the driver here. WARNING: it does require that your machine has a "W Enhanced Trackpad", you do not fear the command line and you actually know your root password for the machine. However I think it's more than worth it - the end-result is a far more useful trackpad without the worries of accidentally hitting hot-zones.

Now if the author of the driver could implement middle click somehow...*hargle*