Mirror universes in Doctor Who - ohW rotcoD ni sesrevinu rorriM

[stargater]

From what little I can find on the subject, alternate universes in Doctor Who seem to function similar to those in other shows/movies. We have "our" universe and there are mirror universes where things are pretty close but just a bit off from "ours". And travel between alternate universes should basically be impossible except for the breach between "our" universe and the one where Rose gets trapped. Alright, we have "our" universe with the Doctor, Rose, Mickey, Jackie etc.. and the "other" universe where Pete is alive, Jackie is turned Cyberman, Rickey is Mickey & the absence of Rose (the dog not counted) so my question is if there could be an alternate version of the Doctor (or other Time Lords even) in this "other" universe. Or do the the Time Lords exist outside of alternate universes? If so, what binds them to "our" universe instead of other parallel ones?

The only bit I could really find on the subject mainly stated how different DW serials that have dealt with alternate universes have contradicted each other in how they work. And I'm just curious. :D