Finally, Dual Booting with iATKOS and Win7

1. First, make sure you partition the drive as GUID
2. Format the OS X partition as Mac OS X Journaled, and the Windows 7 partition as MS DOS FAT
3. Install Windows 7 first, and remember that there is a hidden partition (Win7 would be Partition 3 instead of 2).
4. Then install iATKOS (Mac OS X) and Chimera and you'll be able to Dual Boot.

Thanks to TonyMac