Oswalt for sure declined a $10M 1yr offer from the Tigers (before they signed Fielder.) He has also declined offers at least from the Pirates and Red Sox. It is clear that he wants to play close to home in S. Mo, which makes it either Rangers or Cardinals. After the Rangers trade Koji Uehara, they will have the room and the $ to give him like a $7-8M contract. So I see him going there sometime this week.
The thing that it is important to know is that Oswalt does not have to work for a living for the rest of his life, so he can be picky or retire. On the other hand, this says that he is not been bitten by the bug still, so there is not much fire for playing ball any more... so caveat emptor as far as Oswalt is concerned.