If you are on Mac OS 10.5.x or later then yes, it should be able to read just about everything there is because Bracketeer uses OS X's Core Graphics to import all image files. So, as long as Core Graphics can read it then Bracketeer can use it. That means, however, that users on Mac OS 10.4.x may not be able to read all RAW file formats because Apple stopped updating 10.4 when 10.5 came out, so any new RAW formats probably will require 10.5.

That being said, for the best results you should pre-process your RAW files in Photoshop's Camera RAW dialog before Enfusing them anyway. You should white balance, correct vignetting and chromatic abberations first and then save those out as TIFF files. Then process the TIFF's with Bracketeer.

Is Bracketeer availble for Windows/PC?

Sorry, but no. I haven't even touched a PC since around 1996, so I don't do Windows. However, Bracketeer uses Enfuse to do the actual image processing, and there are other GUI's for Enfuse available for the PC. None of them are anywhere near as good as Bracketeer, but you can check the Enfuse Wiki page for the latest on other GUI's.