USB making? where to start

ok im interested in hardware making for mac. preferably where id like to start is just take a micro controller, some buttons, and a host app on the mac that connects to the device and does something depending on the button presses... You know something simple like that... I have some knowledge in electronics and micro controllers thanks to the arduino project but i want to extend beyond that, preferably using mac os.

Im looking for a decent tutorial thing to get people started

The easiest way for a beginner to allow OSX to interface to non USB micros is to get a PL2303 cable. This is an interface that will plug into a USB port on your Mac and convert the input/output at the other end into standard serial I/O. Just like back in the old modem days. There is a driver for OSX (and windows and linux) from several places.

The standard serial connection will make for much easier interfacing to micro controllers that don't have a USB connection. That being said, you can get a micro controller like Teensy that has a native USB connection and just hooks up to the Mac through a straight USB cable.

If you are talking about a really old (and fun) micro like the 8085 or Z-80 then you will have to go with the first suggestion.