Just wanted to post an active example of ShadowBox as employed on my web-site. I've gotten pretty good at configuring the thing to look and work with just about any web-site. One tip that may be useful to some of you:
If you want to use multiple Shadowbox styles within the same web-site, have them draw/fade differently, etc... I've found that simply duplicating shadowbox.js to shadowbox2, shadowbox3.js ... etc... and then calling the rel="shadowbox2" or rel="shadowbox3" quite useful. You can see this on the "portfolio" link on my page when clicking an image thumbnail.
Have to say this is the best open-source JS I've found for displaying multiple types of content.