This is really shit that noone of Mojang cares for over two months... Maybe it's the fault of the LWJGL - Keyboard.getEventCharacter() is returning 0 in OS X - but it has to be checked by someone...
It's extremly annoying. Even circumflex => ^ isn't available... The strange part is, that it seems to affect both, the JRE of Apple AND Oracle.
It's independent from window mode; AFAIR there was an error message in the console of the first 1.6 launcher like "unknown keycode: 0" or something like that. Unfortunately there's no way to see the error messages with the current launcher / Minecraft version.
This problem hasn't been in 1.5.2
Another Mac OS X keyboard problem is that Ctrl locks if you push the Cmd key, for example when switching the application with Cmd+Tab (function of Alt+Tab in Windows OS). Unlocks by pressing CMD again.
And if you use Ctrl e.g. for jumping the mouse button locks when jumping/swimming up and pressing a mouse button. - Might need an option whether Ctrl+mouse button should count as right mouse button or not, at least in the options.txt.
Java JRE SE 6 from Apple. 1.6.0_51-b11-457 (see Utilities - Java Preferences; for OS X 10.6, since 10.7 there's a JRE from Oracle)
His link leads to this page; I think he tried to link to a folded comment here. => simply read all, aren't that much anyway.