It will be a challenge, because blogging is intrinsically different from book writing. However, if you’ve organized your categories intelligently, you may be able to extract enough material for a salable book out of a year’s worth of posts.
I just posted a quickie guide to getting a book published over at The Copyeditor’s Desk. It’s not the be-all and end-all of publishing advice (it’s a blog post, for petesake), but it does clue you to a valuable resource many writers have yet to discover. Check it out!