To load a module directly into an article is pretty simple in Joomla! 1.5. There is a system plugin which will load it for you. First, make sure the plugin is enabled by going to Extensions -> Module Manager and looking for the plugin called "Content - Load Module." Make sure this plugin is Enabled.

Next, go to Extensions -> Module Manager and find the module you want to load in your article. You can create a new one or copy an existing module, if you need to. On the left side of the module's parameters page, there is a drop-down selector where you pick a template location for the module. However, you can type right there in that drop-down and put in any module location you want. Make something up, and place your module there.

Now, just go open up your article, and use the special {} instruction to load that module right in your article.

Now, when you browse to the page with this article in your front-end, you will see a module loaded right at the top of the article.