Three weeks ago, a Dropbox employee stated on their forum they hoped to have the actual iPad Dropbox app out in "3 to 4 weeks". Let's hope it is imminent. I know too well though how development deadlines can slip, sometimes badly. The iPad is a new platform and while similar to the iPhone platform, it has its own pitfalls and traps. What Dropbox does is the very antithesis of the iPad philosophy, making files visible.
The iPhone version works on the iPad for now. Some report issues on the forum, but I have not seen any. But the best solution is to use GoodReader to access your Dropbox files.