It appears that PayPal has been having some problems with their systems for approximately the last 24 hours (see this forum thread). As a result, if you have purchased a license in the last few hours you may not have received your license information. I have contacted PayPal to try and get the issue resolved and have then send the backlog of notifications; if they do not catch up soon I will start sending licenses manually. It appears that only a small number of people have been affected so far, but I apologize for the inconvenience.
Update: Looks like PayPal have sorted out their issues and sent out all of the delayed notifications (8 November 2005).