where in register.php can I add some custom db inputs....
 

In the register php file, at what point can I add my own mysql query.

Basically, at what point is the user fully registered, but before the page goes to the thank you page... I want to do some certain things with php. I hope anyone can understand this.

And thanks for the help!

Absolutely. Rather than modifying your documents, leave them be and create a hook via the AdminCP.

Goto...
AdminCP -> (left menu) Products & Plugins -> Plugin Manager

Click "Add New Plugin" and point your hook location to register_form_complete. You can begin your PHP modification there. :)

I think you want addmember_complete or something like that.

register_form_complete is executed when the form is displayed, as opposed to when the data is processed.

Thanks for the help... Now if want to use the newly registered persons, id number(example: member.php?u=23

whats the variable name, and is there a list of all variable names anywhere?

Thanks for the help.

If you use register_addmember_complete, I believe $userid is available for use at that point.

I don't know of a list of others available. You can look in the register.php page and see what is defined right before the hook you use.

I've noticed there are no template hooks in the registry pages. Is it possible, without modifying the registry template itself, to add another required field to the user registration process? Any idea on how to accomplish this without modifying any generic vbulletin template?

Thanks

AdminCP -> User Profile Fields.

Marco hit it right on. The easiest way to do it.

What I'd like to do is a little more difficult then that. The field needs to be a part of a plugin (so it would have to be installed when they install the plugin), it must be a drop down box, and it must contain information from a table other then one part of regular vbulletin. It's currently done by actually modifying the registry.php and changing the display of one user defined field, but I want to get out of direct modifications to vb code and templates and make this completely plugin driven.

You will have to edit a template then, if you want to include custom HTML into the Registration Form. PHP code can be placed in a nearby Plugin and then use that to call and evaluate a template. Then use the variable, that the template is evaluated to, in the registration template.