If you're trying to show cms page side content on custom non cms pages, you can study the code of the blog and the List/Links feature which do this. See ViewList.aspx.cs in the blog feature, you'll see it has this line calling a method in mojoBasePage:
LoadSideContent(true, true);
you would need to pass the pageid of the cms page as a query string param to your custom page.
Hope that helps,
Joe