I do not plan on paying someone to steam my dress at all, for the wedding or the photo shoot.
I am going to have my alterations lady steam it when i pick it up after my final fitting and then she is going to turn it inside out. This way if something were to get on it through transit it will be on the inside, not the outside. Once in Florida I am going to hang it in the bathroom when I shower. My mom owns a hand held steamer that she got from Target or Wal-Mart or something. We plan on using that.
I would suggest getting a cheap hand held steamer or hanging it in the bathroom when you shower, this works VERY well. We did that with my sister's veil and it worked perfectly.