10-30-2010 01:53 PM
Currently this is true, only the Air SDK has been released. The Navigator (menu, app swticher) and all the standard apps (that we've seen) such as photos, videos, web browser (excluding rendering engine), are all done in Air though. Unlike on most platforms where Air is a later addition, in this case it's integrated so far into the OS it's basically the native platform.
There will however be SDKs for other platforms arriving. We've got confirmation of WebWorks (HTML/CSS/JS), C, C++, and Java (may just be for backwards compatibility). Based on looking at the source of the simulator I also see what looks like the beginings of Python support.