1. Why not take the whole 8MHz issue out of the equation and run it at 4MHz? Once you get it working at 4MHz...THEN change the oscillator speed.

2. I have some servo code at home. For a 12F629 I think. I'll dig it out and post it later.

3. From what I remember, sending a single pulse of 1.5mS won't center the servo. You have to KEEP sending pulses to get it to move. So if it's at the extreme end, then you have to keep sending 1.5mS pulses until the servo reaches center. AND you need to keep sending those pulses if you expect it to STAY in the center. Some servos are quite a bit slower than others (check the spec sheet).

regards