From this Flyertalk thread we can expect the Starwood Q3 promotion to be announced on August 15th. The next clue about the promotion will be dropped on the SPG forum on or about August 3rd.
I recall the Q3 2008 promotion for Starwood was a you choose promotion. If it is the same this year it will be a great promotion. I think last years was a choice between a few point earning options with either nights or stays, stays counting double towards status, and a few other options.
We’ll post an update as soon as the announcement is made with the details, so check back soon.