MBP will only boot to XP, not OSX

I booted into Boot Camp and my mouse and keyboard weren't working so I couldn't neatly quit it. Turned it off and now it won't boot into OSX at all. Can't use shift to safe boot, can't use option to choose my OS. It keeps booting to XP and, because my mouse and keyboard don't work, there's nothing I can do in XP. The "new hardware" dialogue pops up for everything - processor, slotdrive, networking etc. - so an external USB mouse doesn't work either.

I've put the OSX install one in, hoping it works like an XP one and will let me flatten and reinstall but that doesn't work either; it just boots into XP again.

Is there any way to force booting from CD/DVD so I can wipe the hard drive with gParted and start again?

Are you holding 'C' when you put in the OS X disc?

wow, try (If you havent aready) holding the alt key upon startup, then from there on you can go change your boot prefs and select mac as the main boot.