Many bloggers publish a list of links to related blogs on their sidebar, known as a blogroll. This can be helpful for your visitors, but it can be overdone. You should strike a balance between giving your visitors easy access to useful, outside information, while not encouraging them to leave your site sooner than they otherwise might.
It's counterproductive to link to marginally related sites from your home page because it dilutes your site's "authority" in Google rankings. A better solution is to link to outside content from within individual blog posts when relevant. Build a separate "resources" page on your site where you can point visitors to outside resources without getting penalized for it on your home page.