Does anyone know if this will have some sort of way to trigger a "middle click", like when one clicks on the scroll wheel? As far as I've seen with Apple mice, they've never had support for middle click.
Unfortunately the Macbook trackpad doesn't have middle click natively. However, with BetterTouchTool you can assign commands for 2, 3, 4, and even 5 finger clicks. For five finger click you have to include the thumb. This means that clicking the trackpad with your thumb while a single finger is on it is a 2 finger click, which I prefer to be a regular left click. These are all settings you can control.
Anyway, BetterTouchTool lets you configure a whole bunch of different actions (clicking or swiping in different parts of the pad with a different number of fingers) to activate a whole bunch of commands.
Someone mentioned above jitouch which handles the mm trackpad and the magic pad. I haven't tried it but it looks interesting. Not free though.
Edit: I just tried out jitouch and it works with magicprefs as much as I use it for. I only use magicprefs for the middle click function and the tracking speed. I really like the tap to switch tabs. It's a well made application and only 6 bucks. I think I am going to permanently use it now.