here's a few, does it have to be PIC based?

http://www.discovercircuits.com/D/dingdong.htm
http://www.electronics-project-desig...BellChime.html
http://www.elektor.com/magazines/200...42.lynkx?tab=1 (<= think you might have to register)

This might be of use if you are wanting something pretty advanced.
http://www.datasheetcatalog.org/data.../261251_DS.pdf