jeffheards tastypie format for geojson. Ill update it.

openlayers.format.tastypie.js

OpenLayers.Format.TastyPie = OpenLayers.Class(OpenLayers.Format.JSON, {
    geoJsonReader : new OpenLayers.Format.GeoJSON(),
    geometryField : null,

    read : function(json, type, filter) {
        var results = null;
        var obj = null;
        if (typeof json == "string") {
            obj = OpenLayers.Format.JSON.prototype.read.apply(this,
                    [json, filter]);
        } else {
            obj = json;
        }

        if(!obj) {
            OpenLayers.Console.error("Bad JSON: " + json);
        } else if(typeof(obj.type) != "string") {
            OpenLayers.Console.error("Bad GeoJSON - no type: " + json);
        } else if(this.isValidType(obj)) {
            return this.makeFeatureCollectionFromResultSet(obj);
        }
    },

    write: function(obj, pretty) {
        var output = null;

        if(OpenLayers.Util.isArray(obj)) {
            output = [];
            for(var i in obj) { if(obj.hasOwnProperty(i)) {
                if (!obj[i] instanceof OpenLayers.Feature.Vector) {
                    console.log('should have been a vector feature');
                    console.log(obj[i]);
                }
                var o = $.extend({}, obj[i].attributes);
                o[geometryField] = this.geoJsonReader.extract.geometry.apply(this, [obj.geometry]);
                output.push(o)
            }}
        }
        else {
            if (!obj instanceof OpenLayers.Feature.Vector) {
                console.log('should have been a vector feature');
                console.log(obj);
            }
            output = $.extend({}, obj.attributes);
            output[this.geometryField] = this.geoJsonReader.extract.geometry.apply(this, [obj.geometry]);
        }
        return OpenLayers.Format.JSON.prototype.write.apply(this,
                [output, pretty]);
    },

    isValidType: function(obj) {
        var geometryTypes = ['Feature','FeatureCollection','LineString','MultiLineString','Point','MultiPoint','Polygon','MultiPolygon','LinearRing','GeometryCollection'];
        var containsGeometry = false;
        if(!obj.objects) { return false; }
        else for(var i in obj.objects) {if(obj.hasOwnProperty(i)) {
            if(this.geometryField && obj[i][this.geometryField] && obj[i][this.geometryField].type && geometryTypes.indexOf(obj[i][this.geometryField]) != -1) {
                containsGeometry = true;
                break;
            }
            for(var f in obj[i]) {if(obj[i].hasOwnProperty(f)) {
                if(obj[i][f].type && geometryTypes.indexOf(obj[i][f].type) != -1) {
                    containsGeometry = true;
                    break;
                }
            }}
        }}
        return containsGeometry;
    },

    makeFeatureFromObject: function(obj) {
        if(!this.geometryField) {
            for(var f in obj) {if(obj.hasOwnProperty(f)) {
                if(obj[f].type && geometryTypes.indexOf(obj[f].type) != -1) {
                    this.geometryField = f;
                    break;
                }
            }}
        }

        if(obj.geometryField) {
            o = $.extend({}, obj);
            delete o[this.geometryField]
            return {
                "type" : "Feature",
                "properties" : o,
                "geometry" : obj[this.geometryField]
            }
        }
    },

    makeFeatureCollectionFromResultSet: function (data) {
        return {
            "type" : "FeatureCollection",
            "features" : mapping(data.objects, function(o) {
                return this.makeFeatureFromObject(o);
            })
        }
    }
});