This is a “iPhoto style” inspired Lightbox2 plugin and it auto adds rel=”lightbox” to single- or doublequoted imagelinks in your posts, all you have to do is activate the plugin and you’re set. Click on the image to see it in action.
EDIT: the caption bar (you can see in the preview) aint too beautiful in IE, so i removed it in my installation, since i don’t find it necessary for single images. if you come up with a fix, please let me know.
Thanks to Jan from MacRabbit.com for the iPhoto-looky CSS & images, to Lokesh for the Lightbox2 source and to Várkonyi Balázs for turning it all into a plugin. ♥ Special thanks to Bramus for optimizing the pre-processor code & and for letting me be the pain in the ass that i am, when it comes to fixing code for me.

You sure got that right, hun

[...] Go download Spread the word! [...]
[...] Nay, this is obsolete. But you can find an even cooler plugin here: WP Maczoom [...]
[...] The Chinese: is MacZoomed. [...]
[...] WP Maczoom + Highslide = Fancyzoom 1.0 (although released only now, Panic were the first - if I recall correctly - to have scripted a lightbox/imagezoom to which - in the end - WP Maczoom and Higslide led). Now if only the script were wrapped in a Namespace and/or Object Spread the word! [...]