Module development and code questions

hi, I use upload.module to upload files but I can filter type of file. How can I do that?

How can i create a directory list like the one at http://www.ent.iastate.edu/list/, I can't understand how people make the directories like yellow pages or the one listed on the http://www.ent.iastate.edu/list/ website. Are there any modules available to do it? Are there tutorials on how extra tables can be created in the DB and accessed through custom build modules?

Whenever I try to look for a single page turorial or guide on how to create Drupal Modules, I have to go through piles and piles of information. Is there any most simplest one page guide on How to create Drupal Modules?

hallo,

is there a module for inserting yahoo maps into a
drupal 4.7.0 site?

thanks a lot,
enky.

Can anyone tell me if there are modules in the works that can do something like I'm describing.

Basically you have role-based access control and then another layer of separation into groups.

So you could have a student role and then group their data by class so that each class would have it's own data and it's permission is based on role.

Hello!

Some time ago, I've developed some kind of address book. I'd like now to integrate it with drupal, in this way, that users will see link to it on top or left menu, and after selecting it, they will browse it in the main window.
As I have no expirience with drupal at all, I'd like to ask, what kind of module should I select for this (block, node, etc) ?
Additionally: how can I add something to top menu ? (I've to do it with Drupal 4.5)

best regards