EDIT

function CdmOpenlayersMap(mapElement, mapserverBaseUrl, options){

	var legendImgSrc = null;

	var map = null;

	var layerByNameMap = {

			tdwg1: 'topp:tdwg_level_1',

			tdwg2: 'topp:tdwg_level_2',

			tdwg3: 'topp:tdwg_level_3',

			tdwg4: 'topp:tdwg_level_4'

	};

	var defaultLayerOptions = {

		maxExtent: new OpenLayers.Bounds(-180, -90, 180, 90),

		isBaseLayer: false,

		displayInLayerSwitcher: false

	};

	var mapOptions={

	     controls: 

	       [ 

	         new OpenLayers.Control.PanZoom(),

	        // new OpenLayers.Control.LayerSwitcher(),

	         new OpenLayers.Control.Navigation({zoomWheelEnabled: false, handleRightClicks:true, zoomBoxKeyMask: OpenLayers.Handler.MOD_CTRL})

	       ],

	       maxExtent: new OpenLayers.Bounds(-180, -90, 180, 90),

	       maxResolution: (360 / options.displayWidth),

	       restrictedExtent: new OpenLayers.Bounds(-180, -90, 180, 90),

	       projection: new OpenLayers.Projection("EPSG:4326")

    };

	 var baseLayer = new OpenLayers.Layer.WMS( 

	    "OpenLayers WMS",

	    "http://labs.metacarta.com/wms/vmap0",

	    {layers: 'basic'}, 

	    this.defaultLayerOptions );

	 baseLayer.options.isBaseLayer = true;

	/**

	 * 

	 */

	this.init = function(){

		// get and prepare the Urls

		var distributionQuery = mapElement.attr('distributionQuery');

		if(typeof legendPosition == 'number'){

			distributionQuery = mergeQueryStrings(distributionQuery, 'legend=1&mlp=' + options.legendPosition);				

		}

		// jsonp 

		distributionQuery = mergeQueryStrings(distributionQuery, 'foo=foo');

		var legendFormatQuery = mapElement.attr('legendFormatQuery');

		if(legendFormatQuery !== undefined){

			legendImgSrc = mergeQueryStrings('/GetLegendGraphic?SERVICE=WMS&VERSION=1.1.1', legendFormatQuery);

		}

		var mapServiceRequest = mapserverBaseUrl + '/areas.php?' + distributionQuery;

		$.ajax({

			  url: mapServiceRequest,

			  dataType: "jsonp",

			  success: function(data){

					initOpenLayers(data);

				},

			  jsonp: "foo"

			});

	};

	/**

	 * 

	 */

	var initOpenLayers = function(mapResponseObj){

		// instatiate the openlayers viewer

		map = new OpenLayers.Map('openlayers_map', mapOptions);

		//add the base layer

		map.addLayers([baseLayer]);

		// add additional layers, get them from 

		// the mapResponseObj

		if(mapResponseObj !== undefined){

			for ( var i in mapResponseObj.layers) {

				var layerData = mapResponseObj.layers[i];

				var layer = new OpenLayers.Layer.WMS.Untiled( 

						layerData.tdwg, 

						mapResponseObj.geoserver + "/wms",

					    {layers: layerByNameMap[layerData.tdwg] ,transparent:"true", format:"image/png"},

					    defaultLayerOptions );

				layer.params.SLD = layerData.sld;

				map.addLayers([layer]);

			}

			map.addControl(new OpenLayers.Control.LayerSwitcher({'ascending':false}));

			// zoom to the required area

			var boundsStr = (options.boundingBox !== undefined ? options.boundingBox : (mapResponseObj.bbox ? mapResponseObj.bbox : '-180, -90, 180, 90') );

			var zoomToBounds = OpenLayers.Bounds.fromString( boundsStr );

			map.zoomToExtent(zoomToBounds, false);

			// HACK:

			var hack = "/var/www/";

			mapResponseObj.legend = "http://edit.br.fgov.be/" + mapResponseObj.legend.substr(hack.length - 1);

			// END OF HACK

			if(options.legendPosition !== undefined){

				var legendSrcUrl = mapResponseObj.geoserver + legendImgSrc + mapResponseObj.legend;

				addLegendAsElement(legendSrcUrl);

				//addLegendAsLayer(legendSrcUrl, map);

			}

		}

	};

	var addLegendAsElement= function(legendSrcUrl){

		mapElement.after('<div class="openlayers_legend"><img src="' + legendSrcUrl + '"></div>');

		mapElement.next('.openlayers_legend').find('img').load(function () {

			$(this).parent()

			.css('position', 'relative')

			.css('z-index', '30000')

			.css('top', -mapElement.height())

			.css('left', mapElement.width()- $(this).width());

		});

	};

	var addLegendAsLayer= function(legendSrcUrl, map){

		var w, h;

		// 1. download imge to find height and width

		mapElement.after('<div class="openlayers_legend"><img src="' + legendSrcUrl + '"></div>');

		mapElement.next('.openlayers_legend').css('display', 'none').find('img').load(function () {

			w = mapElement.next('.openlayers_legend').find('img').width();

			h = mapElement.next('.openlayers_legend').find('img').height();

			mapElement.next('.openlayers_legend').remove();

			createLegendLayer();

		});

		// 2. create the Legend Layer

		var createLegendLayer = function(){

			var legendLayerOptions={

					maxResolution: '.$maxRes.',

					maxExtent: new OpenLayers.Bounds(0, 0, w, h)

			};

			var legendLayer = new OpenLayers.Layer.Image(

					'Legend',

					legendSrcUrl,

					new OpenLayers.Bounds(0, 0, w, h),

					new OpenLayers.Size(w, h),

					imageLayerOptions

			);

		}

	};

	/**

	 * merge 2 Url query strings

	 */

	 var mergeQueryStrings = function(queryStr1, queryStr2){

		if(queryStr1.charAt(queryStr1.length - 1) != '&'){

			queryStr1 += '&';

		}

		if(queryStr2.charAt(0) == '&'){

			return queryStr1 + queryStr2.substr(1);

		} else {

			return queryStr1 + queryStr2;

		}

	};

}

(function($){

	$.fn.cdm_openlayers_map = function(mapserverBaseUrl, options) {

		var opts = $.extend({},$.fn.cdm_openlayers_map.defaults, options);

		return this.each(function(){

			var openlayers_map = new CdmOpenlayersMap($(this), mapserverBaseUrl, opts);			

			openlayers_map.init();

	 	}); // END each

	}; // END cdm_openlayers_map

})(jQuery);

$.fn.cdm_openlayers_map.defaults = {  // set up default options

		legendPosition:  null,			// 1,2,3,4,5,6 = display a legend in the corner specified by the number

		displayWidth: 400,

		boundingBox: null

};