Module development and code questions

I've migrated from WordPress to Drupal after having set up Drupal for four sites and loving it more and more each time - so now I'm getting into module development because I figure it's best to put all of my modifications into one module for easy portability and upgrades rather than hack a dozen files.

I'm working on a project for a small insurance agent. I would like to develop a module, or use a combination of existing modules to offer online insurrance quotes. The process might look something like this:

Hi and thanks for taking the time to read this. I love this kinda thing and love tinkering. I've encountered a couple problems while playing with the banner module. Some which have been easy, others... yea :)

Apache 2.x
PHP 5.x

I recieve 2 errors one in the logs the other in the apache logs.
I cannot reach the banner settings in admin (blank page), but am allowed to add new ones and the code seems to work (views counter keeps increasing) with code in appropriate spots in the theme or in a block/flexiblock

Hi!

I checked through module development documentation, but I am not sure how to do this.

Can modules create content independent from default Drupal's page creation flow?

I'm working on my first module and I have a question. I am trying to insert a script tag into the html head area. I've done the module tutorial and I've looked at different modules that do this (event, taxonomy_dhtml, simplenews). I'm a bit confused because all three use differerent hooks and none of them are working for me.