Actually it does help your rankings to out link to relevant resources, it does so in logical manner of the way internet operates. Since internet is inter connected network of networks, and the binding glue is the hyperlinks, so if you have a resource (whether the resource is an article, blog post, web page, video or anything else for that matter) out linking will help as far as Google rankings are concerned. First Google follows links to identify resources, and if you have an outlink to relevant resource then it will follow that, thus you improve your own relevance, furthermore; if you have out linked to more useful resources on internet, then the internet visitor who found you through Google, will not go back and search Google again (you automatically increase your own relevance factor) so out linking is less talked side of SEO and most webmasters shy away from it thinking it is not smart. At least you are thinking outside of the SEO circle and thinking about both "user experience" and Google rankings. Therefore, my personal suggestion for you would be to make no mistake about it, and out link when ever you can.
I have made a blog post exactly for this question you are posing here http://ish.re/1KXM I hope that helps answer your question further