When will Dreamweaver be available for use on an iPad or Android tablet?
Probably not for awhile. Dreamweaver is a professional level web development tool. Furthermore, web design is still very coding heavy unlike a drag-and-drop interface of design so most people who code would probably still want a keyboard for entry vs. a touch screen (could you imagine typing hundreds or thousands of lines of code on a touch screen?). I'd suspect that the layout programs would be done before Dreamweaver in the cycle. So don't hold your breath.
At least, for now, full-on Dreamweaver is not available for either Android or iOS, however there is Adobe Proto, which is a prototyping wireframe creation tool for website design in the field. The resultant files are supposed to readable by Dreamweaver, though I have not used it.
When I think of the kind of file management I do to make a website, I cannot imagine doing all of that on an iPad. My production computer typically has Photoshop and Dreamweaver open, I regularly use Bridge to rename image files and I frequently use Fireworks to do batch re-sizing of photos. While one can do a certain amount of photo editing on the iPad, one does not have all of the available tools one needs in Photoshop. Frankly, I don't know how I could make a series of images for a jQuery banner on an iPad.
I can see using an iPad as a photo editing tool with it connected to a desktop and used as a design tablet, like the Intuos Cintiq, but that's about as far as it goes, presently.
North America
Europe, Middle East and Africa
Asia Pacific