Ehrman's presentation seemed to be a pretty standard summary of Misquoting Jesus. He began with "How We Got the Books of the New Testament," where he pointed out that in most cases, Christians are not reading the New Testament, i.e. what the evangelists wrote, but a translation of what they wrote. Beyond which, those translations have not been based on the originals, because we don't have the originals. We have copies of copies of copies of copies, etc. Ehrman asked what the 'original text' was in the first place, recognizing that the means we have today to produce and reproduce books were unavailable to the ancients, and that if they wanted a copy of a certain text, they would have to copy it by hand themselves. When books are copied by hand, people make mistakes. You don't know if the guy before you got it wrong, and so you reproduce his mistakes, and you add in your own, from the original, all the way down the line. When you get deep enough into transmission, and you have scribes attempting to correct mistakes, you now have three components: the original text, the mistakes made in copying the original, and the mistaken corrections of the mistake.
Ehrman continued to speak about the copies of the original, and the copies of the copies of the copies. He also introduced the fact that our earliest copies are at least 100 years later than the originals, so it's not as if we have them to correct later texts against. And the earliest complete copies of manuscripts are from even further away then those.
Ehrman's next major point was to deliver some information on "The Surviving Copies of the New Testament." At this point, he gave a fairly standard summary of the state of NTTC: 5500+ Greek manuscripts, 94% of which are after the 9th century. He spoke of John Mill's apparatus, producing 30,000 variants from only 100 manuscripts. Finally, he made the point that NTTC was an odd discipline, in that the more manuscripts there are to work with, and the more evidence there is, the more difficult the job of reconstructing the original becomes. He closed this point that there are "more differences in our manuscripts than there are words in the NT."
Following that, he noted what kind of mistakes were present in the manuscripts, going over accidental mistakes (misspellings, homoeoteleuton, crazy stuff such as copying across two columns instead of down a single column, as was the case in ms. 109).
Finally, Ehrman took a look at intentional alterations, highlighting three as he closed: the pericope adulterae (John 7.53-8.11), the longer ending of Mark, and "the angry Jesus" in Mark 1.41.