gistfile1.txt

Paul,
Yep you can continue to use the same key, and  you'll want to https://node01.public.learningregistry.net/publish for the url rather than https://node01.public.
learningregistry.net/.
For the payload we're asking people to use a machine readable format based off of microdata, LRMI and JSON. 
Here is an example we created from Khan Academy's API
    {
        "items": [
            {
                "type": [
                    "http://schema.org/CreativeWork"
                ], 
                "id": "urn:www.khanacademy.org:node_slug:e/absolute_value", 
                "properties": {
                    "name": [
                        "Finding absolute values"
                    ], 
                    "author": [
                        {
                            "type": [
                                "http://schema.org/Person"
                            ], 
                            "properties": {
                                "name": [
                                    "Marcia Lee"
                                ]
                            }
                        }
                    ], 
                    "url": [
                        "http://www.khanacademy.org/exercise/absolute_value"
                    ], 
                    "dateCreated": [
                        "2011-08-29T00:00:00Z"
                    ], 
                    "educationalAlignment": [
                        {
                            "type": [
                                "http://schema.org/AlignmentObject"
                            ], 
                            "id": "urn:corestandards.org:guid:71F96ADF450A4133A258FDACE2D3910D", 
                            "properties": {
                                "alignmentType": [
                                    "teaches"
                                ], 
                                "educationalFramework": [
                                    "Common Core State Standards"
                                ], 
                                "targetName": [
                                    "CCSS.Math.Content.6.NS.C.7"
                                ], 
                                "targetDescription": [
                                    "Apply and extend previous understandings of numbers to the system of rational numbers"
                                ], 
                                "targetUrl": [
                                    "http://corestandards.org/Math/Content/6/NS/C/7"
                                ]
                            }
                        }
                    ], 
                    "learningResourceType": [
                        "exercise"
                    ], 
                    "description": [
                        "Find the absolute value of a given number."
                    ]
                }
            }
        ]
    }
The fields are documented at http://www.lrmi.net/the-specification, we're currently working on a formal doc describing the JSON

I believe we're having people use the payload_schema
"application/microdata+lrmi" 

Thanks if you have any other trouble let me know and I'll do my best to help get them sorted out.