A list of links on Writing and Grammar by Gian Trotta.
I'll list it here for easy reference:
Sun Microsystem's Web Writing Guide Shines
Copy Editors List Their Biggest Gripes...
As The Chicago Manual of Style Goes Interactive
Strunk's Elements of Style Stand the Test of Time...
And Traditional Grammar's Drop-downs Will Pick Up Your Skills
The Slot: A Curmudgeon's Guide to Style
Copyeditor.com's Worth a Quick Visit
Edit-Work.com: Two Texans' Straight Talk on Style
The Copyediting-l Mailing Is Out, But Votes Are In
A Professor Targets Common Errors in English
And Another Helps You Master 'Notorious Confusables'
Grammar Slammer Picks Up the (Spell)Check
Grammar Now: Instant Answers to Your Writing Woes

I think I should add some of these sites to the side bar.