Last week, Metro quietly published a developer site to publicly release GTFS data (the backbone of Google Transit) at http://developer.metro.net.
Today, they announced it in a press release: L.A. Metro Releases Transit Data to Spur Applications Development and Grow Ridership. In the release, they say the Developer Site "is one of a number of exciting interactive developments that will be announced in the coming weeks."
This can only mean one thing, that Metro will soon be on Google Transit. I know that there are some upcoming schedule changes because of the new Gold Line Extension, so that may complicate the release of schedule data, but I would expect Los Angeles to be able to use Google Transit in the next month or so. Of course, if this doesn't happen we'll tell you what you can do to apply pressure.
Join the Los Angeles Wants Google Transit Facebook Group to keep updated on the push for Google Transit.