Bethesda took me behind closed doors with a small group of other media guys and showed us on HD projectors a demo with a Mad Doc developer playing Star Trek: Legacy. Afterwards, they took us downstairs to a room and let us play Star Trek Legacy and Star Trek: Tactical Assault (on both PSP and DS), hands on.
Star Trek: Tactical Assault for the DS plays exactly like Starfleet Command 1 for the PC. A few of the more advanced power management functions have been removed, as has the campaign map (just missions), sadly, but for the most part in game it feels exactly like Starfleet Command. The PSP version had graphics pretty close to Starfleet Command 3 without the glowies, much better than the DS version, however I found it a pain to control since you have to memorize a ton of button combinations to corrispond to each and every single option on the ship, from overloading weapons and shields to power turns and stuff like that, and there is no on screen HUD. So I'd say the DS version is superior. They even said that the goal was to make it a handheld Starfleet Command successor. In fact, Quicksilver was literally called up and asked, "Hey, do you guys want to develop a handheld Starfleet Command for us?"
You can choose to play the DS version with buttons (ick) like the PSP version, or entirely with the touch screen. My preferred control method was to hold it with my left hand and my left thumb on the D-pad (up and down control impulse speed, left and right allow you to turn) while using my right hand to hold the stylus on the touch screen. While you could use the touch screen to turn while on the navigation panel, it was easier to just hit left or right and hold it until it reached the proper angle.
Star Trek Legacy is supposed to be Bridge Commander's spiritual successor, spanning all generations of Star Trek starting at TOS and going straight back to Voyager and DS9. Interestingly, they designed it firstly for XBox 360 controllers, though keyboard and mouse can be used- the demoer showed it running on Windows XP, but played it through a wired XBox 360 controller plugged in to the PC via USB. It controls very well, and feels somewhat like Bridge Commander with some SFC elements thrown in. Feels better than Bridge Commander. The demoer was a Mad Doc developer who previously worked on Bridge Commander, so a lot of inspiration was taken from it. However, it's got very impressive fleet command stuff; during a Borg Cube battle you could press the Back button on the 360 controller and get a map, and select ships and order them to attack, or take direct control over any ship at any time. Stunningly good graphics, too.
I forgot to ask the developer (I'll probably email him later, I have his number now), but I asked one of the Bethesda workers in the hands-on room and he said that while the game was currently being developed for Windows and XBox 360, porting it to PS3 or Wii was still being considered.
I'm DEFINITELY buying Tactical Assault; I might even pre-order it. Great game, true handheld SFC successor, even down to the one-hit-kill asteroids. Sad that there's no online play, but if the game sells the guys I talked to said that they had actually talked about online play and possibly dynaverse and it was very likely to be in any sequel that might be made.
EDIT: Oh yeah, and they wouldn't let me take pictures. No cameras allowed inside.