I have been trying to make my Mac application enter fullscreen now for a while but can\'t get it to work. According to the Apple developer center, I should use enterFullScreenMo
Lion has some new APIs for full screen.
To do it with NSWindow, do this
[window setCollectionBehavior: NSWindowCollectionBehaviorFullScreenPrimary];
To do this with NSApplication do this
[[NSApplication sharedApplication] setPresentationOptions:NSFullScreenWindowMask];
A bit more about it here.