Mostly insecure databases run by companies thinking that SQL injection doesn't affect their systems.

No I mean where can I find a list of let's say yahoo emails and passwords. Check out this article:

http://www.nbcnews.com/tech/security/2-million-stolen-passwords-facebook-twitter-google-yahoo-others-leaked-f2D11691630

Where the fuck are they? How do I find the passwords taken from these sites?

Most of the dumps Solidus is talking about can be found if you Google around. A lot of the dumps are either put on pastebin or torrent sites.

In the case of the (not-so?) recent LinkedIn hack, the list of password hashes is available here: http://dazzlepod.com/linkedin/

If you want emails too just learn to search better, I suppose. And/or find some SQLi in a popular forum and cross-check the passwords against the email accounts.

Finally, you can buy such lists on various websites using TOR.

Hang out on IRC. fubar used to dump shit like that all the time. I think 99chan's IRC has calmed down now but I'm sure there are still many wild west style servers floating around.

infinity chan where anything is possible