I released the new version 4.2 of jQuery Colorbox today. Check it out 
Get it here.
If you have any problems, then please report them at the WordPress Support Forum
Changelog:
4.2 (2011-10-16)
- NEW: Danish translation by Michael Bering Petersen
- NEW: Vietnamese translation by Techfacts Computer Magazin
- NEW: added option to remove the link to the developers site from the WordPress meta-box.
- BUGFIX: “Automate Colorbox for all other images” now again works as intended. (functionality broke in 4.1)
- BUGFIX: fixes “Undefined index: colorboxAddClassToLinks” error
- BUGFIX: got rid of PHP’s XML-RPC methods, also plugin checks now before calling XML-related methods.
- CHANGE: Updated Colorbox version to 1.3.18
Is it still not possible to add a width and height to the colorbox, together with the link class? I still think that would be very nice, because of opening colorbbox windows for youtube content. My video’s or flashfiles have all kinds of different sizes.