Yes, the two Fremont plans have fallen-through. The A's aren't seriously exploring any locations other than San Jose at the moment. Oakland is trying to put a proposal together and the A's have said they would consider it, but it appears that SJ is their primary focus at the moment. Of course, that would mean the Giants' territorial rights would have to be adjusted.
The best source for A's new stadium news is the
new A's Ballpark blog. He also covers other teams/stadium issues when they have some relationship or possible insight to the A's situation.