Hi,
If you run the PIC at 1MHz and set the TMR2 prescaler to 1:16 then the lowest possible frequency, ie with PR2=255, would (if my calcs are correct) be around 24Hz, 1/(256*4*2.5us*16). If you run that thru an external flip-flop you'll get a divide by 2 ratio so you're down to 12Hz AND you'll get your 50% dutycycle for free - without having to change the dutycycle registers when you change frequency. You should be able to reach 1200Hz with this setup, ie PR2=1 the PWM frequency would be 3125Hz which, after the external 1:2 divider would give you 1562.5Hz. However, the granularity or resolution at the top end will be far from great.

What else, except generating this frequency, is the chip going to do?

/Henrik.