If you can only have one resource in your writing arsenal, then consider Purdue OWL. Many of you may be intimately familiar with this spectacular resource, but for those of you who aren't, you'll be grateful to have found it.
Not only does the Online Writing Lab (OWL...get it?) overflow with the answers to all those pesky "how do I word?" questions, but it's FREE! No need to buy a tired and prunish copy of *insert your high school English teacher's favorite go-to source for all things writing here.* Simply navigate over to the site and browse to your heart's content. It's not just for writing research papers.
Bookmark the site and use it often.
Follow the blog via RSS for updates on what's happening with Blue Spider Press.