I have been struggling with setting up the alpha1 version of 3.0 for android using Eclipse on Ubuntu12.04; and have failed (cocos2dx-2.2.1 works fine though). There were some bugs in the release which seem to have been fixed in the development trunk and I think I have another issue to report. I’m new to cocos2dx so I can’t say for sure if it is a bug or what.
.project file in samples/Cpp/HelloCpp/proj.android has a reference to COCOS2DX/cocos2dx, whereas it seems that since the release of cocos2dx-3.0, the directory structure has been changed. And no such directory exists. instead, it has been split into COCOS2DX/cocos/2d. Please look into this if it is an issue.