This is by Alan Hunter [alan@thsresources.com]. It was published on alt.humor.puns.

There once was a man who just went by the nickname “411”. He had access to all the best narcotics and anesthetics. He would go around the town with a hypodermic needle, searching out pay phones. Upon finding ones that are dilapidated and in need of some serious help, he would inject the cord on the receiver with Cocaine, novocaine, lidocaine, michaelcaine, or whatever. One day, as he was doing his thing, a police officer approached him and asked, “What the heck are you doing?!”

411 answered very matter of factly, “I’m a phone number, for your information!”