Standard TargetsI've reduced the pre-built and source-version-controlled targets(.hex and .lst files included in the git repository) to just thethree basic 16MHz targets: atmega8, atmega16, atmega328.
Those are both 16MHz bootloaders. This one is 8MHz:ATmegaBOOT_168_atmega328_pro_8MHz.hexI don't believe an 8MHz version of Optiboot comes with the IDE, but I re-compiled it for 8MHz and uploaded it here:http://arduino.cc/forum/index.php/topic,101064.msg760450.html#msg760450When using the internal RC oscillator instead of a crystal, it may or may not run close enough to 8MHz to allow serial comm (and therefore the bootloader) to function without errors. I've had pretty good luck though, and I think others have as well; many of the chips seem to run pretty darn close at least at room temperature. Just be aware that it may be a bit of a crap shoot.