i'm dual booting 12.04 and lion on my late 2011 macbook air. very simple. install refit in OSX. you may have to reboot several times or do a complete shutdow

i'm dual booting 12.04 and lion on my late 2011 macbook air. very simple. install refit in OSX. you may have to reboot several times or do a complete shutdown before the refit bootloader will show up. then it will be a very familiar install from there. you can use the mac disk utility to partition your drive beforehand. i haven't tried bootcamp, so i can't comment about that.