Welcome to HBH! If you have tried to register and didn't get a verification email, please using the following link to resend the verification email.
whitch sites are easy to hack?
Sites that arnt very SQL secure and those of the above. also look for robots.txt on sites eg www.whitehouse.gov/robots.txt
Google is absolutely amazing at finding vulnerable sites.
Can't remember that site that specialises in it, though. hackwithjeremy.com? Ha ha, something like that. If anyone knows it, say.
Anyway, you can use Google to find sites using outdated versions, it's pretty easy. Say you found a SQL injection flaw from somewhere like securityfocus.com, you could see it's in version "1.2.3" and Google "Powered by Lameforum 1.2.3" and voila.
This is VERY script kiddyish, though.