Add this method to help you build the tree
// add keys to an object as a tree
// ["a", "b", "c"] will generate
// a { b: { c: def } }
// def is the value of the leaf node
var AddToTree = function(obj, keys, def)
{
    for (var i = 0, length = keys.length; i < length; ++i)
        obj = obj[keys[i]] = i == length - 1 ? def : obj[keys[i]] || {};
};
Create a function for a jQuery selector that will convert the form in an object
$.fn.serializeObject = function()
{
   var o = {}; // final object
   var a = this.serializeArray(); // retrieves an array of all form values as
                                  // objects { name: "", value: "" }
   $.each(a, function() {
       var ns = this.name.split("."); // split name to get namespace
       AddToTree(o, ns, this.value); // creates a tree structure
                                     // with values in the namespace
   });
   return o;
};
With these two functions define you can set an event on the submit button:
$(":submit").click(function(e){
    // contains the object from the form
    // respecting element namespaces
    var obj = $("form").serializeObject();
});