Paypal is well aware of this kind of scam and has pages on its website that discuss it. An important thing to look for in such emails is that actual emails from Paypal always open with "Dear (your name)", not "Dear Paypal User" or "Dear Paypal Subscriber". Another ways you can check is to view the full header of the email message that will indicate its true origin, unless that's been spoofed. Instead of deleting such messages, I tend to forward them to spoof@paypal.com to help them fight phishing, as it's called. If in doubt, forward the message to spoof@paypal.com and wait for an automatic reply before clicking on any links in the message.