I can't find a video online but Newt Gingrich was really angry last night about the results in Iowa. He was particularly mad at Mitt Romney, who he felt had run a negative campaign against him.
There is always a lot of discussion about whether the correct strategy is to run a positive or negative campaign. Pundits spend a lot of time speculating about how voters will respond to each type of campaign. However, in this case it seems pretty clear that a negative campaign is the correct strategy for Romney.
Romney is at best a mediocre candidate and a mediocre guy. He is untrustworthy but his views are generally acceptable to conservatives and he seems genuinely competent. He also doesn't seem intolerable as a person but he's not first on my list of people I would want to hang out with. This has been the case for 6 years and ads that list his accomplishments and show him smiling with children aren't going to change this perception. As a result, his best strategy is to spend his money showing people that Gingrich is corrupt, Paul is a nutbar, and Santorum opposes contraception. I think this is what he will continue to do.
Update: Here's the speech