Here's the scenario:

For any given piece of content, I have Metadata definitions for what thumbnail, title, etc. to use if this piece of content is appearing as link in a sidebar. It will appear in this sidebar because a main piece of content has it selected as related content. I am putting this related list of content onto the page with a contentlist control - this shows the correct links to the related content. How do I call metadata definitions in a custom xsl file so that I can display the thumbnail and other items I have defined as metadata for the items in the related content list?

I don't think you can get the metadata from xsl. So you will have to do this by API. Here is a sample

    Dim metadataList As Ektron.Cms.CustomAttributeList

    Dim contentMeta As Ektron.Cms.CustomAttribute

    Try

    ' Getting all the metadata information from the MainContent

         metadataList = MainContent.GetMetaData()

         newCustomList = metadataList.GetItemByName("Related Content").Value

         imgBanner.ImageUrl = metadataList.GetItemByName("Banner").Value

         menuLeft.DefaultMenuID = metadataList.GetItemByName("Menu").Value    

    Catch ex As Exception

    End Try