http://www.urbandictionary.com/define.php?term=in%20the%20know

1. in the know

With knowledge of something."People in the know are aware of a nuclear explosion if even the slightest jolt was made upon the renegade carrier."-part of the storyline for Blast Corps

2. in the know

1)to have intimate knowledge of a particular subject not necessarily every subject.

2)to be privy to uncommon knowledge

you know who Gwyneth is dating?

ask Rita she's in the know

3. in the know

To know all of what is happening at any given time; to have a lot of friends and connections."Yo man, I'm bored.. anything going on tonight?""Why don't you call James? He's in the know."

"I gotta find someone in the know, so I can pick up some weight and get my business off the ground."