Adobe has thus far offered few details of their upcoming Creative Suite 4 release, but that is set to change September 23 with a webcast where they'll detail major changes that have been made to Dreamweaver and Fireworks as well as some developments in Photoshop and Flash.
We should note that this is not the release date but rather the official unveiling of CS4. Those wishing to participate on the webcast can sign up here. Adobe has not announced when Creative Suite 4 will ship, or how much full Creative Suite packages and upgrades will cost - they did, however, release preview editions of Dreamweaver, Fireworks and Soundbooth back in May. Apple Insider has some more detailed information of what to expect from CS4.