When I change themes, all the icons I have put into folders and all my hidden icons become visible again on the desktop. Is there anyway to change themes, while maintaining my current folder and icon formatting?
No, you have to manage the icons you want for each NEW theme you load, if you keep a couple on there, you can set them up the way you need, and switch between those and they will be the same as you set them up.
However, if you delete a theme from your phone, then say in a week you want to install again, in my experiances, it will load up the way you had it.
Rachel hit the nail on the head. Correct in that every new theme you need to manage your folders all over again. Also i downloaded a theme i had on my Curve like a month ago and it loaded back the exact way i had deleted it.