Ok I don't know how truthful any of these are but I have read that they work, but you know the rule of the internet don't believe everything you read
One suggestion is to tie your nipples in a noose using string or whatever you have and pull. Or better yet strap yourself to a chair or something so your upper body can't more forward then with your nipples tied, pull and tie the string to a pole or whatever so that they remain pulled for lets say 5 minutes at a time. Do this every few days and eventually you should see result.
Personally I don't know about this one.
Something like this mind you seems like a possible solution that might work
http://www.amazon.com/Nipple-Triple...id=1408854797&sr=8-16&keywords=nipple+suckers