Let's say that you're viewing a node, in this case you'll have access to the $node variable. From the $node variable you can gain access to the object that this node points to. The object contains info about related objects. The following example template code shows how to get access to the related objects:
I think Rob means something else: a list of objects that link to the linked object too.
That is currently not possible. Even more, when an object relation is defined as an attribute, the link goes into the attribute values table. The code posted above is for the generic object-object relations instead.
To have that information, one should write either an operator that queries the attribute value table (or the ezcontentobject_link table for generic object-object relations) or add this as a content method to the datatype object relation.
For the datatype object relation list, this involves even XML parsing as far as I understand from the code.
It is an interesting functionality though, as it allows to build "topic maps"