Hello,

If you are planning to use a 8051 based microcontroller, I would suggest the DS5000T...its perfect. We had planned to use it, but was not available at the time we were developing our project(too costly).

http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2946

Its got wonderful features, you can program the uC code using Hyper Terminal. Just send the Hex file. It has a RTC, you have have any number of timers.

Regards
Raj Shetgar