Simple question, simple answer.   Let's say you want to tell a user what version of the solution they are using.   Technically the way the InfoPath works they don't need to worry about that, but let's just say you wanted to tell them.   The following code shows you how to grab a node and push the solution version value into a text field associated with the node.   Thanks once again to Scott Heim for this snippet.

                var objField1 = XDocument.DOM.selectSingleNode("//my:myFields/my:field1");

                objField1.text = XDocument.Solution.Version;

Easy as pie.