i bought my wedding dress from davids bridal in early 2009 for my october 2009 wedding. i also thought that i would end up needing a 24 or larger, but i ended up being able to get a 18 1/2. it was great!! )
My wedding dress came from Alfred Angelo. It was like a 16W I think. They were really helpful with ordering something that would be flattering. They even had a few dresses in the store in the right size so that I could make sure of the fit. This is pretty rare with smaller boutique-feeling stores, so I definitely appreciated that. I had a cossetted dress so that a little pre-wedding weight loss (or gain--ouch) would be workable.