I downloaded Android Developer Tools Bundle for Mac from here. The System Requirements section says it needs "Mac OS X 10.5.8 or later (x86 only)". I tried to start Eclipse.app in adt-bundle-mac-x86_64/eclipse, but I got the following error message:
You can't open the application Eclipse.app because it is not supported on this type of Mac.
I have a Macbook with 32-bit Intel Core Duo CPU and Mac OS X 10.6.8 and JRE 1.6.0_39. Why can't I start Eclipse from the ADT bundle? If I install Eclipse Classic 4.2.1 32-bit from here, it works.