How to force a theme to use a sitewide custom menu Ok so Im coming from wordpress where I could just hook a menu into the header of every page and create my own custom menu. I'm trying to do the same with drupal but it's so confusing! Im building my own custom theme so if I can start small with this question. How can I insert a sitewide menu with a custom template onto every page of the site. Something like this.

&lt;div id="top-menu"&gt;
   &lt;---hooked in functions from the template.php---&gt;
&lt;/div&gt;
How can I insert a sitewide menu?

You can use Context to insert menu blocks into regions. 
Contexts can be set to be site wide. 
Make sure that your theme supports the region into which you are inserting the menu block.  The region should be defined both your theme's .info file and also it's relevant templates (generally the page template).

Making a menu with a custom template

You can use the devel_themer module to sniff what templates you can implement to override the menu's default theming.