You can do it the same way you check for nofollow on any URL. View the source and do a search for rel="nofollow". There are also some firefox plugins that will tell you too. But I am not too familiar with them. Good luck.
One of the best ways to check if a link is no follow or do follow is to download SEO quake. http://www.domainstructure.com/2008/07/do-follow-tips-and-tricks-for-blogs/ Information you may find useful.
This is what I use as well, and I was about to recommend it but you beat me to it! You have the option to put line-through nofollow or noindex links, so you can easily and quickly see if links are dofollow or not.
I do agree with this one. I have used it to find do follow blogs and also forums because you can really see if those forums or blogs are exhibiting do follow links?
When you pass link in forums then right click on your link go to properties tab see the Will open in option in Link properties tab if it mention "new window" then link is do follow and if it mention "no follow" then the link is no follow.