Many forums have all links as no follow but you can request the admin to add your site to the whitelist making it a do follow link
http://www.namepros.com/ http://www.talkfreelance.com/ http://www.bloggeries.com/ http://www.9mb.com/ http://www.webmaster-talk.com/ http://www.ukwebmasterworld.com/ http://www.webtalkforums.com/ http://www.estetica-design-forum.com/ http://www.csschat.com/ http://www.talkdev.com/ http://www.templatesforums.com/ http://www.warriorforum.com/ But I'm not sure if all of them are dofollow.
Some I know are: http://forum.bicellphone.com http://forum.primenotebook.com http://fashion-model.org/
Most forum owners will allow links in Sigs,,, for quality posts.. But will keep an eye on the quality of the post.. If all they see is... Great,. Nice post,. or Thanks... Then your A@@ is out the window..
Thanks for the share... will register one by one on those sites... coz I want to build more backlinks through forum posting now...
I don't agree. Every link is useful. Even from website that have nofollow, even with low pagerank. A link is always a link and can give traffic either way.
Most of the forums allow us signature linking but post should be on the topic and signature linking should be limited not too much Spam.I think 2 signature are good but 4,5 or more than that make it spam.