Stuart demonstrated a shared disk product from LaCie that did just that. Plugged it in and it came up as a file share, a web page for admin, and even a streaming music server in iTunes. Great stuff.
Another great technology is wide area zeroconf where you can grab a Bonjour control panel and add extra, non local, domains to it that will be searched as well. This multicast DNS stuff works on a local subnet, but I was wondering if it would also work within a hotspot at an airport... it does, I'm on a T-Mobile hotspot at Seattle airport and above is the visible shares I can see via the bonjour browser in Interarchy.
Clearly there's a potential security problem here and Mac users should be aware that their name and machine is visible. I had a look at the web pages that showed up and they were just the Apache welcome page in both cases.