It won't be too long (I hope) before you can download and use RTM_TimerCalc, a free Windows desktop application that will generate Arduino PWM code from parameters you supply!
TimerCalc will calculate your Timer (1,2,3,4 or 5) Arduino Code and Control-Register settings for your wanted;
- Frequency (exact or you're told the closest possible)
- Interval (if you're looking for timed Interrupts)
- Duty Cycle (per sliders you set up on a Preview Display!)
- Interrupt Code (available via handy checkbox, includes Prototype ISR code in code comment)
- PinMode Settings (pin numbers and Output channel IDs supplied in comments)