Well ... some of them at least.
http://bgr.com/2014/04/15/heartbleed-checker-passwords-change-list/
More important, is to understand that until the particular site is patched for the Heartbleed bug, your password & other data remain at risk. If you change your password today, on a site which has not been patched, your new password may be hacked tomorrow.
Take home message: most important is to change your password after the site in question is patched.
More about Heartbleed & how it works. / vulnerability vulnerable exploit exploiting hack hacker hacking theft OpenSSL sensitive data server revealed attacker usernames passwords credit card numbers dangerous allow access server's digital keys impersonate servers decrypt communications major new security vulnerability severe implications entire Web Internet bug server server's memory sensitive user data stored private data usernames passwords credit card numbers extremely serious issue Netcraft Internet research firm information protect protected security experts log into accounts afflicted sites patch patched problem confirm fix progress customer service teams information John Miller security research manager TrustWave security compliance firm Yahoo OKCupid sites caution red flag change passwords security experts confirmation fix further activity vulnerable site security patch change passwords sensitive accounts banks email first two-factor authentication another piece of identifying information /
