Well he was active on the forum just yesterday, so it's not like he doesn't have access to a computer. Has he not been replying at all, or just hasn't provided shipping info yet? If he is not replying at all, I would give him one more week and then file the dispute.
I just sold a hood last Thursday, and despite being in the middle of two major holidays, and the fact that I wasn't even taking care of shipping, I made sure it got out today. I originally said it would go out earlier in the week, but again, due to the holidays it got pushed back. However, I still kept the buyer updated after missing the first timeframe, I didn't leave him hanging for weeks.
I agree with Jeff in that it hasn't even been two weeks, but it's not that hard to drop a box off, and if he's not responding at all, that's different. The only time someone stopped replying to me on here was when I told him the product he sold me broke, and then he disappeared for a year.
Of course, innocent until proven guilty, hopefully it's just a minor lack of communication and it all works out.