4 weeks. Trust me, four weeks. Then you get a nice email, something along the lines of...
"Your Submission to The Yellow Pages"
Your gallery has been accepted and will appear on the site soon.
http://#
(might take up to a few weeks though)
Basically, you get the confirmation after about 4 weeks, and you'll be listed in 2 or 3 days time, the most I had to wait was a week after the confirmation.
Oh, don't forget Thumbzilla. I remember when they were having problems a few months ago. They lost all their submissions, and had just fixed it. I submitted, and was listed within 12 hours.

One time only.

But they do send a nice email saying that you have been accepted, and if not, they tell you why (no bullshit reasons like Richards Realm)