The best official word you will get is the road map, which was just published Sept 11th, 2009, by Michael Rozlog. There may be a new Road Map published soon, but until then, that is the best official word.
From what I understand (most of which is in that road map, or was from the Delphi Live! Labs sessions which you can catch the videos of on my site,) Delphi Project X (which I am assuming is going to be the next version, but it may not) is going to focus on cross platform compilation.
Version after that is I believe going to be Commodore, which is the 64 bit version.
There is also some functional programming and multi-threaded features that are going to be mixed in there someplace.
That road map, even though it is from September, is prior to the Weaver / 2010 release of Delphi, so I am expecting a new road map soon. That one should have a more clear view of what to be expected. Keep in mind that these are their goals, and they are subject to change as they go along. The further our the goal is, the more likely it is to change as things move forward.
As far as releases, they seem to like releasing in the fall. So in the September, October, November time frame next year. Of course that is all purely conjecture. Yadda, yadda, yadda. So don't make any plans on this.