I think there are already many threads with this topic. So you can find out yourself if you search around this forum.
Anyway, for you I'm giving some links :
http://www.hostbidder.com (Here you can get free TLD by posting).
http://www.domain4free.com (Here you will get free TLD but your website must have good traffic, otherwise your application will be rejected)
http://hyperwebenable.com (here you will get free TLD for your blog, but here also you need a blog with good traffic)