Adobe has made statements that they will support OS X and has shown a bit of Photoshop working in the past. A few weeks ago I sent email to many of the major software vendors and Adobe said that they intend to announce product after the introduction of OS X. There was no guidance on what that meant.
Steve Jobs was asked that question generally during the quarterly analyst call (not Adobe specifically, but important software vendors). He suggested that there would be a small number of applications available by the Summer of 2001 and a larger number afterwards. He noted that Apple has a large number of folks (150 if memory serves) working with software vendors and it is intended that the number will increase after the release of OS X. In his traditional way of finding silver linings Steve noted that there are already many applications available from small 3rd parties.