Sigma announced that they've provided Adobe with information to do lens correction in Photoshop CS5. When the proper CS5 Lens Correction filter profile is selected, it should correct distortion, chromatic aberration, and vignetting based upon Sigma's information. This, of course, makes one wonder whether Nikon has provided information to Adobe about their lenses. I believe the answer to that question is no, though CS5 will still ship with a number of correction profiles for common Nikkor lenses. It is still unclear how new lens profiles will be created and shared (there is a Search Online button in the Auto Correction tab, which seems to indicate that Adobe will be maintaining a database of lens profiles, and that this will grow after CS5 ships).
I would point out that Adobe is late to the game with this feature, and it still isn't in the conversion module where it belongs (which implies it won't be in Lightroom 3). Capture NX2 has done this since introduction, Bibble Pro has this ability, DxO is of course known for making lens corrections, and there are plenty of third-party options, with the most commonly used being PTLens. Differences exist between corrections, too. PTLens and DxO are the only ones I know that fully remove complex mustache or wave distortions.