I'll be honest, I didn't read his site too often, but I most certainly knew of the work of Andy Olmsted.
He blogged under the name G'Kar at Obsidian Wings, and I just saw (by following a link from digby), that he died in Iraq.
hilzoy has a post up about Major Olmsted, and it's a wonderful tribute. Here is the introduction:
Andrew Olmsted, who also posted here as G'Kar, was killed yesterday in Iraq. Andy gave me a post to publish in the event of his death; the last revisions to it were made in July.
Andy was a wonderful person: decent, honorable, generous, principled, courageous, sweet, and very funny. The world has a horrible hole in it that nothing can fill. I'm glad Andy -- generous as always -- wrote something for me to publish now, since I have no words at all. Beyond: Andy, I will miss you.
My thoughts are with his wife, his parents, and his brother and sister.
The main part of the post is a note written by Andy, who had asked hilzoy to publish it in the event of his death.
Please go read the whole thing, including the wonderful comments.
hilzoy asks only that politics stay out of the comments.
Update [2008-1-4 19:26:33 by taylormattd]:
JR has written a lovely diary about this, and it includes some of JR's favorite posts by Olmsted.
Update [2008-1-4 21:41:57 by taylormattd]:
From the comments, here is a link to the Rocky Mounty News blogs, where Major Olmsted wrote. There is a picture and a obituary. There are also links to his posts.
Update [2008-1-5 2:43:31 by taylormattd]:
Another tip from the comments, here is Olmsted's personal blog