Your best bet is trying to find a drycleaner who specializes in wedding dresses and can package it away properly for you in a special box once it's cleaned.
I got my dress dry-cleaned by the shop I bought it from (although this was done around 6 weeks after the wedding). I'd bring it to a good dry-cleaners and enquire. My dress-shop also supplied me with a storage box, but these can also be bought direct from [broken link removed].