Many clocks on Google search for PIC Basic Pro, but here is a nice one I have used myself:
3 Button adjustment of a DS1307 RTC
"The circuit uses a PIC16F84 and a standard 16*2 LCD.
.. tested the program on the following Pic chips, 16F84, 16F628(7), 18F1320(1220) and 18F452(252). "
http://anonym.to/?http://wiki.picbasic.org/index.php?n=ThreeButtonadjustmentofaDS1307RTC.RTCAlso easy to modify to SPI bus. I used it on a clock with good results using DS1305.
For clock only, a RTC is a little overkill. My application had a time display function when in standby, so I had to use a RTC. Very easy!