Here's a nifty little resource from the Charlotte Observer (via FDL) for info on each of President-elect Obama's cabinet choices. The nominees still need to be approved by the Senate, but there's little doubt they'll have any trouble with that.
When you click on the graphic below, you'll see an interactive list of the cabinet departments as shown below. Click on each department to get a brief overview of the nominee and the department's functions. It's very helpful if you're as forgetful as me.