With the pending release of Moodle Mobile (the official app) I’ve gone ahead and updated the Mobile services matrix located at http://lmspulse.com/mobile/.
I haven’t yet tested the official app but included some links and quick notes gleaned from the development page (http://docs.moodle.org/dev/Mobile_app). If you’re not ready to update to Moodle 2.1 but want Mobile functionality check out the matrix, complete with reviews and testing notes. My personal favorite for 1.9 is the free and very easy/useful MLE: http://lmspulse.com/2010/mobile-app-review-mle/.
Enjoy and chime in on the discussion at our Mobile page.