I used duct tape to adhere red rosin paper to protect my newly installed prefinished hardwood floors and left the floors covered for about 16 months as my renovation continued in another part of the house. I used Lift-Off (comes in a blue container), which is available at both Home Depot and Lowes and is similar to Goof Off, but not as harsh, to remove the duct tape residue. It didn't harm the finish on my floors, as far as I can tell. I love this product.

I've used the product listed below to remove old silicone caulk from shower doors. It works!

If the duct tape adhesive has already reacted with the finish on the floor there may not be any way to prevent damage to the finish. Spray the tape with the cleaner, let it soak overnight and then use a plastic spatula or credit card to gently pry the tape off. You may have to do more than one treatment.

I believe you can find the cleaner at Home Depot or Ace stores.

Here is a link that might be useful: cleaner

WD 40 will remove residue in seconds .

Another very effective goo remover is tea tree oil. It's sold in the pharmacy section at WalMart. It's expensive but works wonders on tape and price tag stickum. I don't know what it might do to the finish on your wood so be careful.

Ditto to the WD 40