Mass Effect 2 - Interview @ Polygamia

Polygamia has a Mass Effect 2 interview with Producer Adrien Cho.  He avoids answering a number of questions but does seem to confirm Day 1 DLC:

Will you release any DLC linking the first and second game? It was two years, so some people might not remember everything.

I can't talk about the details yet, but there's definitely some DLC that will tie the two together.

And will we see it before the release of Mass Effect 2?

After, very soon after.

Will we have any day 1 DLC, like with Dragon Age?

Yes, we will have content available. We can't say yet what it is, though.

Will the DLC be more like Dragon Age? Will we hear a signal coming from outer space saying "If you want to help me, please buy some stuff from us"?

Again, the DLC plan hasn't been fully announced yet. But there is a lot more variety, from new weapons, new armor, new sidequests to big expansion packs. So there will be a wide variety of things. And we really want to reward fans of Mass Effect, so there will be a lot of bonus content provided in the form of DLC.