Hello Ross,

Ross>>1) pic12F629 has the capacity to be run at 20 Mhz - does that include using the internal oscillator? For example, if I put DEFINE OSC 20 at the top of my code (After @ DEVICE pic12f629, INT_OSC), will it run at 20 Mhz?<<

The chip has the capacity to run at 20 MHZ, but the chip only as a internal OSC of 4 MHZ (The data sheet will give you this info)
this means you must use a external OSC to go faster than 4MHZ, and set your programmer to ext OSC.

Ross>>2) Can I use one external oscillator for two PICs, or should they each have their own?<<

Never tried it... but the main problem you "might" have, is too much load on the OSC...resulting in Meltdown and temporary death to your computer...the only fix to such a death, is either using the internal OSC, or isolating your chip with a buffer from your Ext Osc.

Dwayne