This is a really nice add-on. I used this as a basis for one I made for vB4... some changes I made (in case Andreas ever makes an "official" version for vB4):
- Updated for vBulletin 4.
- Instead of using [highlight], I decided to extend [code]. It uses it if you specify a parameter like so: [code=javascript]
- I'm intercepting [html] and [php] BBCodes to use this automatically.
- Reads all available languages (from the geshi language directory) so just having the file in the directory displays it as being available on the BBCode help page (see example).