Web Grognards

One of the longest-standing sites for war-gaming, having been online since 1995 - golly, that's 12 years (at the time of this entry)!
If you don't know what a 'grognard' is, then this site is probably a bit niche and not for you, although the term is explained on their front page.
But if you are into war games, this may well be the richest oline resource for rules translations, errata and variants etc., you could ever hope to find. There's even material here on some titles you might not think of as war games, eg., Age of Renaissance, Euphrat and Tigris, Merchant of Venus and others.
They have an updates RSS feed, although its behaviour has been inconsistent with one of my readers.

Web-Grognards