Sparkle, Andy Matuschak's software update framework for Cocoa applications, is no stranger to TUAW. Now, it's found its way into WebKit, the developmental version of Safari. This feature, often requested on the WebKit mailing lists, allows WebKit to update itself with the click of a button.
Sparkle has become a standard for Mac applications. I tend to shudder a little bit every time an application has the smarts to tell me there's an update, but then sends me to a web page to download it. Not because I'm lazy, just because I know there's a better way. There are several variations cropping up, including one from Google. I haven't worked with the newcomers, but I can testify that Sparkle is so utterly simple to implement that developers who fail to do so should be scolded repeatedly until they capitulate (see WebKit). A hearty thanks, though, to the WebKit team, from all of us who surf the bleeding edge of browser development.
Thanks to Chris Pirillo for the tip!