Module development and code questions

So what exactly is the difference between calling a module directly and calling it via a menu? In my module, I have this little snippet under mymod_menu(...)

Hi

I am a drupal newbie somewhat, on my third build and am currently working on a broker's property site and am at my limits with Drupal. Before getting flammed, I should state I have built many sites dependent on CSS, since the days of HTML 3 and when Blue Robot was the only source of documentation online. I took a 3 year haitus from the web world and am back at it, at the beginner's level with PHP, so you'd have to bear with me.

I had chosen Drupal because the marketing has been great for it and for its pleasureable ease with modifying the themes, but the important stuff like module support seems heavier with Wordpress.

I have been trying to make listings using CCK, Contemplate, Imagecache and got something working, but not quite the banana.

I need the listing to look like the following URL:

http://www.gammonrealtygroup.com/category/listings/

That is done with 'Custome Field Values' module in Wordpress. It would be a shame and a waste of countless unpaid hours to have to port over a theme template created for Drupal to Wordpress.

Tried working the Views module, but that either doesnt do a thing being it is a dev module or I am absolutely clueless with implementing it. Views sounded like the save-all solution, but I new feel lost with it.

is there a module that I can use that will allow me to make templates within drupal and then send them out as news letters?

I am using the guest book module, and would like to change the order of the forms in the user settings screen. (Guest book comes up before the user's password field and is confusing)

I know there is a way to set weight on individual form elements, but is there a way to set the weight of a form itself?

Thanks.

How do I get my homegrown module to override a theme function from another module?

E.g. My homegrown module (let's call it qdiscount) wants to change the way product price is displayed. This is normally handled by the function theme_product_price in ecommerce/product/product.module.

Now, I know that if I have a theme called e.g. mymarine, then I can define a function called mymarine_product_price in mymarine/template.php, and that will override theme_product_price.

Is there a way to manage images which have been uploaded with for example fckeditor. So A module which scans a directory with files, check if the files are in the source of the nodes ()
and if they are not in the source there must be an option available to delete those images.