My paypal account is $0 and I never feed money into it. When I have to pay for something it just comes directly out of my checking unless I tell it to use the credit card associated with the account. As said before you probably don't have a CC on the account so it waits for that money to clear before sending it off. They prefer you have both a CC and bank account so that one backs up the other.
If you're the type that would rather not have your CC or debit card out there consider going to your bank and getting a separate CC just for use on line. Just tell them you only want a limit of $X amount on that card. Another way would be to get a prepaid card but the fees aren't worth it IMO.