Affected users have also been informed by email. Note that the email has no links in it. Visit the Linkedin website directly to change your password. If you receive an email saying it is from Linkedin asking you to change the password which has a link, be careful. It might be a phishing email.
LastPass has created a tool that allows you to check if your password is compromised.
On other notes, if you’re an eHarmony user, you might need to change your password as well.