LinkedIn has confirmed that at least some passwords have been compromised in a major security breach.
For a detailed explanation of the breach, click on this PCWorld link
It might be wise to consider the proactive move of changing your passwords to your LinkedIN account.
I used the same password for my LinkedIN account, my Facebook account and a number of other accounts. Though the report suggested that other information (such as e-mail address, name etc) was not breached, I chose to change all my passwords and have now selected different passwords for different applications.
If you have a LinkedIN account, and use the same e-mail address and password combination elsewhere, you might consider changing your passwords, just to be safe.