If you have a Mac, pop the SD card in the reader, pull off your photos and then reformat the card with Mac disk utility.
If you got a Windows PC, try to use a virus scanner to repair the SD card. If the repair is successful then copy your photos off the card then reformat the card using Windows. If the virus repair is unsuccessful, you can still try to copy the contents of the card to your PC and reformat the card with the PC.
Let us know if you have any luck. I don't recommend reformatting THEN trying to RECOVER the photos... some photos will be rendered useless with this method.