This is good news for me, as my old copy of Elements 3 won't work on Leopard at all (I know, I'm a cheapskate). Some of the new goodies in version 6 include a new Quick Selection tool and tabs for quickly jumping between different functions. This version also makes it super easy to create photo books, greeting cards and more.
Adobe Photoshop Elements 6 runs on Mac OS X 10.4 Tiger and Mac OS X 10.5 Leopard (so PowerPC-users aren't left out in the cold). A single license will cost you $90US, though registered owners of older versions can upgrade for $70US with an in-box, mail-in rebate (or via adobe.com).