"If you have the capability to burn a new bootloader (i.e., a programmer) you can burn sketches directly to the ATmega.
I think with Arduino 0011 the easiest way to change the clock speed in the code is to create a new board type (in boards.txt) and the appropriate parameters should propagate to the code."
Hmmm. That's a good idea, buuuttt...I don't have a parallel port on my laptop, and I don't have access to our desktop that DOES have one, only when I absolutely need to burn a new bootloader, and I'm going to want to be able to upload new sketches all the time. How can I get the bootloader on the actual microcontroller to accept a 20Mhz crystal to I can upload sketches through my USB port as I used to?