Lots of good writers still make grammar errors. So why not spend 6 minutes trying to correct them? There are plenty of good grammar sites on the web, but Grammar Girl has won me over with the quick episodes and useful info. Not to mention her sharp wit and lovely voice. If you're looking for a place to start, try i.e. versus e.g. or the comma splice (where she correct Scott Sigler - lots of geek cred). Here's the iTunes link.
P.S. Ms. Grammar Girl, I know I make many mistakes on this blog but I promise to do better.