There is an Itsy Bitsy Teeny Weeny Yellow Polka Dot Preview of Hidden Springs from Joystiq Yesterday. Check it out below!

Are you still unable to get even a smidgen of forgiveness from your Sim family for locking Aunt Debby in a doorless closet until she died in a pool of her own self-mess? Maybe a trip to upcoming Sims 3 expansion Hidden Springs is in order!
A magical museum, a rustic lodge and a little mystery are all waiting for your Sims in the DLC. You’ll just have to figure out how to stave off a revolt until you can buy it on August 25.

Source: The Sims Hub