Start looking in the yellow pages for Bridal Shops and ask them for a recommendation for a seamstress who could alter the dress for you.

A bridal shop likely won't do it for you, many if not most work only on their own merchandise. But someone may point you to a former employee who has started her own alterations business. Ask the tailor or seamstress for references from other brides.

I have done this kind of thing three times. One thing I can warn you about: surprisingly enough, white and ivory are hard colors to match. The brides I worked with were (fortunately) more concerned with sentiment than whether I found exactly the same shade and texture of "oyster white."

Another thing: taking a wedding dress apart carefully isn't rocket science, but it is a time-consuming process. Re-working a wedding dress could easily take twenty hours or more. (I think the last one I did took twenty hours.) If the seamster or seamstress is experienced and talented, a re-design or even just resizing could cost as much as a new dress off the rack. Last summer a woman wanted me to make an old (but free) wedding dress five or six inches longer, and larger (to fit a pregnant bride), and was shocked that it would cost more than a hundred dollars.

You might be able to find a seamstress who'll work for ten dollars an hour...but this is not the kind of project that you want to give to the lowest bidder.