MadMatt has a guide to mods at the CMHQ website There are also several sites that compare mods, see Kump's CM Outpost (recently back in business so don't know address) and Pawbroon's Mods and Modders
No, CMBO is not compatible with OS X, nor will CMBB be either.
To my knowledge, CMMOS is for the poor saps stuck on Gates-controlled machines. There is also a CM Mod Manager for Mac at CMHQ.