If your password was leaked, your login to LI will be invalidated and a password change required. Likewise, if you use the same password on other sites, change those as well. It’d be pretty safe assumption that your personal details from your LI (or accounts on other sites which use the same PW) to have also been compromised.
As a lesson, if you haven’t already, use a random password generator. I was thinking of re-opening my LI account after closing it about half a year ago, but I think it can wait. Expect LI’s stock price to take a beating when the market opens in the morning (http://quotes.wsj.com/LNKD). Also note this comes a day after a PR fiasco involving LI’s iOS mobile app transmitting contact and email information in plain text form.
Official press release – http://blog.linkedin.com/2012/06/06/linkedin-member-passwords-compromised/
Check if your password is leaked (you can submit your original password or the hash): http://shiflett.org/blog/2012/jun/leakedin