See Dan Gayle's comments from the original version of this post:
http://typophile.com/node/58385

I looked at the link, but Graublau is not showing -- it's defaulting to Helvetica.

Graublau showing for me in Safari.
Hey Tim, it's a bit more work, but I think it's worthwhile to use the Microsoft Weft tool to make a linkable EOT file for these things. As unfriendly as it is, at least you only have to make the file once.
Everybody with Windows has IE to fall back to. (Retreat!)
Makes looking at examples a lot more reliable.

@Nick: Hmm. Are you visiting the page via a browser that supports @font-face?
http://webfonts.info/wiki/index.php?title=@font-face_browser_support

You can also check out the screenshot (Safari/Mac) and critique that way:
http://nicewebtype.com/fonts/graublau-sans-web/images/graublau-sans-web.png

@Richard: It would be worthwhile, I agree. But so many other things are worthwhile too. ;) I think I'll wait for services like Typekit to do that EOT work for me.

I have updated this specimen:
http://nicewebtype.com/fonts/graublau-sans-web/

... as per the best @font-face syntax I know:
http://nicewebtype.com/x/u

... and will attempt to continue revising as time goes on and new methods exist.

Rich, I sincerely appreciate your holding me accountable for making sure things work in IE/Win. More people need to care, as you do (and as I do), for an unbiased experience. Not necessarily the same experience http://dowebsitesneedtolookexactlythesameineverybrowser.com  ... but an unbiased experience in that, if there exists the capability, no agent should be segregated. I trust you won't stop reminding people to pay attention to their entire audiences.