You're not listening when I say that there are times a PIC alone is unsuitable for an application.

Hardware PWM will not go down to the frequencies you required (consult your PIC's Datasheet if you don't believe me). PBP's software PWM doesn't allow for frequency changes. However if you insist on the PWM route, you may like to do a search for 'Slow Software PWM' or 'SSPWM' in the MeLabs archives that I directed you to on another thread. I cannot comment on the software or it's suitability, but I'd calculate that generating nice sine waves will have a major software overhead.

Why don't you just use a CTCSS encoder/decoder chip (like an MX165CP) and have the PIC control that? A simple web search will give you heaps of ways of generating CTCSS tones cheaply and most can be interfaced to a PIC quite easily... example...

http://www.xs4all.nl/~pa0nhc/Project...038encoder.htm

Melanie