Jason,
I haven't used an RTC chip yet. I have a couple DS1307 samples but just never tried them.
One thing I wondered about though... How would I use the RTC chip. I imagined that I would read the time and date from the chip during power up into variables and then simply 'bump' them during a 1 Hz interrupt from the DS1307 "SQW" output. And so I would maintain Alarm, Timer, Calendar, and Clock variables (and logic) in my program. Some other examples I've seen simply read the DS1307 chip over and over again.
Maybe I'll hook up one of the DS1307 chips to play with...
Mike