I don't get my iPhone 4S for another two weeks or so, but in the meantime, a bunch of online posts demonstrating the 4S camera have had me salivating to get my hands on one. Camera+ posted a comparison between the 4S and a bunch of other cameras this morning. This video shot on the iPhone 4S (via Gruber) is also extremely impressive.
The video below has also been making the rounds, comparing a video shot on the 4S with a video shot on the Canon 5D Mark 2 (camera body = $2400):
I'm looking forward to getting my own. Expect impressions here when that happens.