There is a really great interview with Jon Favreau over on comingsoon.net. You should read it right now.

Here is a snippet,

CS/SHH!: Would you launch into another two year movie after this?
Favreau: Yeah, I would do it. Hopefully we'll figure out how to get "Iron Man 2" going and I'll be involved with that. You have got to out-do what you did before. So, if the last one took two years, we would need at least that to do what we are talking about, or at least thinking about. Nobody knew about "Iron Man," and that was a disadvantage in some ways, but nobody expected anything. I think people were pleased based on the fact that they had no preconceptions about the project. Now, we have a movie that people seem to like and you can't give them less. You have to give them more. There are challenges that come with that as well as the benefit of people already understanding who he is and the character. We told the origin story so where do you go from here? There are plenty of story lines to explore from the 40 years of history from that character.

CS/SHH!: Have you chosen anything?
Favreau: No, we haven't. I haven't been hired to do it yet. I know that Robert and I have talked a lot about what types of things we would like to do, and how to play into the strengths of what we discovered last time around. I look forward to rolling up my sleeves. Hopefully that won't be too long in coming.

Jon also discusses, Avengers, possible plotlines for Iron Man 2, the DVD release, Incredible Hulk, and what he is currently up to. All can be found here.