[youtube]BX009oYRBSE[/youtube]
My new logic analyzer made with a ATMega168. The user interface is programmed in Processing.
The chip has a 1000 byte buffer, and so does the computer, it runs fast enough to capture stuff on a I2C bus.
Source code and rough documentation here
http://franksjunk.thespudmall.com/logicanalyzer.zip