I recently got a Nikon D3000 and I cannot get the memory card to format. I've read the directions, taken the memory card out of the camera, formatted and reformatted, I even taken and downloaded some pictures, but sometimes when I turn on the camera it says it needs to be formatted. Is it a faulty memory card or is it operator error?
Welcome to Nikonians! Sorry to hear of your problem. It sounds like a bad card is the root cause of your problem. Get a new card as George recommends. Format the card in the camera. That should solve your problem. If the new card works without problems, return the bad card if it is new or has a warranty. If not discard it. You may loose your images the next time you use the bad card. Good Luck and Enjoy your Nikons!
Another thing that you can try is to make sure that the memory card (SD) write-protect switch is not in the lock position. It is in the top left corner of the card. Just move the switch up. In the lock position, it allows you to write and delete photos but not to format the card.