The following blogs aim to keep grammatical foibles in check:
Literally, A Web Log, tracks abuse of the word "literally." You'll literally flip over the entries -- oops.
Apostrophe Abuse, even pings the New York Times for mussing up an apostrophe.
Groaners are overused, hackneyed phrases that ignite "a firestorm of controversy" in news writing.
Grammar Hell, urges you to fight back against "brutal assaults" on language.