I'm running Processing 2.0b8.  In android mode, the right arrow button "Export Signed Package" says it is not implemented.  I guess in older versions of Processing, it was just "Export" and that used to work (all the tutorials I've seen that talk about getting a Processing .apk rely on being able to click Export).   So I tried 1.5.1, and that claims that Android was not installed on my computer correctly (it is).  Lastly, I noticed that on the processing.org download page, it says

Note that  Android mode  no longer works in Processing 1.5, you'll need to use an alpha or beta release to do Android development.

In other words, if I want to use android I must use the newest Processing version, but if I want to export I can't.  But I see you people distributing apps for Android-- how do you do it?

Sort of related, I notice this issue is listed as critical, and was posted....3 years ago.  Bummer.   http://code.google.com/p/processing/issues/detail?id=222