Expert DHTML / AJAX coder wanted

We are looking for an expert DHTML / AJAX coder to help us add interactive elements to our existing web application. Our current application uses standard forms and requires pages to reload normally. We would like to add interactivity, similar to the type used in facebook. This will include: ? ? 1) Loading different forms on the same page, based on a user's request. 2) Expanding and contracting elements on the page. 3) Creating help notes that "float" over text boxes and table cells. 4) Showing a loading icon while data is being retrieved from the server. The code must be able to work cross-browser and should preferably be generic, so we can reuse it across different parts of? the application. In addition, we also need to be able to display content from both left to right, and right to left, so that we can support foreign languages.