EA and BioWare have been pushing their new Baldur's Gate-esque RPG Dragon Age: Origins pretty hard for the last year--on the PC, that is. It's no surprise they're leading with the PC version of the game, given the company's pedigree as a PC RPG developer. There's also the fact that the game lets you control multiple characters at the same time, each with a couple dozen different combat abilities assigned to multiple keys and icons on a talent bar. It's a lot to keep up with, even with a mouse and keyboard at your disposal.
I'll answer the big question first: How do you manage all those abilities and attacks on a gamepad? You can map three abilities to the face buttons (one each to X, Y, and B) and then a second set of three abilities, toggling between the two sets of three by holding a trigger. Like on the PC, you can pause the combat indefinitely to issue commands to all your party members, and doing this on the console version is how you get to all the rest of your abilities. So you'll have access to the full run of powers here that you'd also have on the PC, you just won't be able to use as many of them in real time without stopping the combat.
Movement also seems a little streamlined. On the PC, you can click to move your character, or you can use a WASD setup to move them around directly. On the consoles, direct character movement via the analog stick seems to be the only way to move. You can still pull the camera out to the old overhead top-down perspective on the console as well.
Based on my brief demo, it seems like Dragon Age is fully functional on the 360. My gut feeling is that you'll be best served playing the PC version if you have the option, but if you do all your gaming on a console, you can rest assured you won't be missing out on much--if anything, since BioWare is continuing to refine and test the console controls--by playing one of the console ports.