Adobe has posted a PDF detailing compatibility with Mac OS 10.5 here.
However, the following CS3 applications will require updates for full compatibility with Leopard: Adobe Acrobat 8 Professional and our professional video applications, including Adobe Premiere Pro CS3, After Effects CS3 Professional, Encore CS3, and Soundbooth CS3. We expect to publish free Leopard compatibility updates for the video applications in December 2007 and for Acrobat 8 Professional and Adobe Reader 8 in January 2008.
Older versions of our creative software will not be updated to support Mac OS X Leopard.
Biggest factor for me is that Lightroom isn’t compatible with Leopard yet:
Photoshop Lightroom 1.2 is not fully certified for Mac OS X Leopard, but future updates will address areas of Leopard compatibility
Thanks to Marshall for pointing that one out. Photoshop CS3 is compatible with Leopard.