Skinny,
The Silicon chip circuit should work well for what you need. The source code for the PIC is available
Here and should be modifiable to what you need. Depending on you programming abilities, you could modify the code to use the mains 50Hz to generate a timebase for your clock as it already generates an interrupt for the zero crossing detection.
If you do play around with the SC circuit then you should always unplug it before touching it. For people who haven't seen the circuit, the live(active/phase) from the mains is connected directly to Vdd on the PIC :shock:
Mike.