If you're looking to add this .phtml script inside the middle of a CMS page, you can paste that text right into the content area of the CMS page's WYSIWYG editor. Magento will know to parse the text out, detect the block, and render out your view script.
Note: your "template" attribute includes too much, you only need to specify the path afer the "template" directory. A name to your block is also required, otherwise it will not be rendered. So, it should be more like this:
{{block type="core/template" name="my_distributors_block" template="page/distributors.phtml"}}
I'm going to assume this .phtml file, despite being located in the "page" directory, is just a small block which you'd like to render within a page. (NOT an entirely new page layout). If this "discributors.phtml" script is indeed a page layout, then this answer is not what you're looking for.
Lastly, you really should be putting this .phtml file within your own theme directory, not base. Unless this view script belongs to an extension which you plan to re-use for multiple projects. I'd suggest reading up on how to configure Magento to use your own theme, and the fallback logic Magento uses to find view scripts.
