AVR-Chat

Hi, 
 
 I'm working on a design utilizing an ATMega88, and it's pretty full up. The 
DebugWire interface is what I would like to use to program the chip in 
production, but to turn on that interface, apparently you need to set 
something using the serial interface. 
 
 However, I need to use one pin of the serial interface(MOSI I think) as a PWM 
output. I'm concerned that during normal operation, any sort of header would 
just turn into an antenna at the PWM frequencies I'm using. 
 
 Has anyone run into this and discovered a convenient way to do double duty in 
this scenario, or am I hosed? 
 
 I'm not opposed to going to just a Serial programmer, but the same situation 
applies there as the same pin is being used. 
 
 Thank you for any suggestions, 
 -Micah