From the CHIRP web site -
CHIRP is a free, open-source tool for programming your amateur radio. It supports a large number of manufacturers and models, as well as provides a way to interface with multiple data sources and formats.
The basic idea is that rather than learning the peculiarities of your radio's programming interface, you use CHIRP which has access to databases like Radio Reference and RepeaterBook to find the channels you want to have easy access to. Programming the device should just be a matter of loading in the set you want, attaching your radio to your computer via a programming cable, and selecting "Upload to Radio".
My new radio is on its way, so I'll update this when I get it to work! So far the application was easy to install (you have to install a Python runtime on OS X before it works) and it was easy to get the Washtenaw county repeater list from RepeaterBook.
UPDATED: It worked the first time! Here's what I had to do to make it go smoothly.
First, before you upload channels to your radio, you have to download its current configuration. This gets all of the settings out of the system.
Second, after you are done uploading the channels, unplug the programming cable from the radio. This should be obvious? but somehow it wasn't. Once I unplugged things everything worked just fine.
Third, make sure that you pick the right radio that you are connecting to or else unpredictable things can happen.
I found the walk-through at Miklor's CHIRP Software Guide to be useful and helpful, and it suggested some additional features (like setting channels to be receive-only) that will probably get me to re-program the radio a few times before I'm done.