In reply to Sonya Mc:
You can use the funds that the buyer has sent to print out a paid for postage/courier label directly from ebay; as soon as you can enter a valid tracking number from royal mail, the rest of the money will clear.
It's also worth checking if the money has been put into your paypal account already... In spite of that warning, mine went directly in, and I was free to draw it out into my bank account directly.
If the buyer has paid via paypal you essentially already have the money, but it's in administrative limbo; Not sending the item because ebay won't release the cash is both rubbish for the buyer and could cause you to loose seller privileges or even your account with EBay if the buyer kicks up enough of a fuss.