Through October 15, Hyatt is offering 2500 bonus American Airlines miles per stay (registration required) on top of the normal 500 miles. That’s 3000 miles per stay, even for 1 night stays.

This isn’t Hyatt’s planned third quarter promotion, and in the Flyertalk thread speculating on what that will be, Hyatt’s Gold Passport representative posted an interim offer of 1000 bonus miles per night on the following airlines:

AA-American Airlines
2v-Amtrak
JL- Japan Airlines
NH- All Nippon Airways
QJ- Jet Airways
TA-Thai Airways
UA-United Airlines
US-US Airways
WN-Southwest Airlines

For this bonus, you need to call and ask to enroll in bonus promotion TP30K2010. It runs June 15, 2010 through September 30, 2010, and it’s been confirmed that you can get retroactive credit for stays you’ve made back to the start of the promotion.

While this hasn’t been made explicit yet, it appears that the two bonuses should be stackable provided of course that you are crediting your stays to American Airlines miles. Clearly you can’t earn the American Airlines 2500 bonus miles per stay offer and a bonus 1000 US Airways miles per night since you can only credit a given stsay to one airline program.

But if you register for both promotions then a one-night stay should earn 4000 American Airlines miles during the promotion period. A three night stay should earn 6000 American AIrlines miles.

Update 7/16/10: Hyatt has posted an update on Flyertalk that American is not participating in the 1000 mile per night bonus after all. So while the bonuses should have been stackable, you can’t earn American miles with the per night bonus. The per stay bonus is still valuable, of course, but you have to choose 3000 American miles per stay or the bonuses offered by the other carriers.