Just change your LinkedIn password
The other day it came out that millions of LinkedIn password hashes were leaked. Of course everyone with a LinkedIn account wonders if their password has been compromised. This has led to a bunch of put-your-LinkedIn-password-in-this-form-and-I'll-tell-you-if-it-was-leaked websites. This is a perfect example of the Password Anti-pattern; it's a pattern you want to avoid.
If you have a LinkedIn account you should just change your password. Don't go putting it into other sites to see if it's been compromised because the second you've entered it you've compromised it yourself. And if you're one of those people that uses the same password in different sites, then I suggest you change your passwords on all those sites too.
While we're on the subject of changing passwords allow me to commend to you my previous posts on the subject.