The incident in question was when Lewis tried to pass Jenson at the hairpin. Jenson overshot it, and Lewis thought he was simply opening up a gap to make it easier for his countryman to get to the pointy end, as he apparently had already in other races. Jenson wasn't though, he had just misjudged the apex and turned in on Lewis and they made contact.
I guess after the race Jenson made a snide comment about how many other incidents Lewis had in the race, and when he discovered that actually Lewis drove an otherwise clean race, he apologized. All very civilized. Good for them both. I remember during the race Lewis seemed quite concerned and apologized to the team saying he thought Jenson was letting him through.
Interesting there was no anger from Hamilton in this case...he must really like Jenson.
http://www.bbc.com/sport/0/formula1/28393576