This is an excellent article written by Idan over at vBhackers.com that walks you through some of the basics of writing your first vBulletin modification/hacks. The article also has links to other articles written to help you understand exactly how vBulletin handles things such as the datastore.

Hope this helps.

[How-To] Simple hack development stages - vBHackers.com - vBulletin Modifications, Hacks, and Help

Thanks for this! Will come in handy!

kill
bleed
boil