$Post. Handling Replies

$Post. Handling Replies

OK, I've done some looking around on the web, and there are some tutorials but a lot of them are above my head.  I'll explain the main goal and ask my specific question.    The main goal is to submit a large form to the database, and if it is successful, direct the user to a specific page. Initially given my experience level I would have loaded a page and passed the form data to the new page via $_GET.  That page would save the data and if successful, notify the user and provide a link for them to click to get to another page.  Well, the form data can be very large (lots of textarea's) and I am concerned that it could possibly become larger than 2048 charachers (apparently a limit that IE has).  Plus I decided it would be a good idea for me to learn other ways to approach this problem. 

I want to use jquery post to saveform.php, saveform.php will enter the data into the database and then if it is successful must return something (XML...?)  the user will be notified that the form has been saved and the page will be redirected to a location where they can choose to enter a new form.  

Ultimately I have 3 areas that I need help with

1. The $post() code
2. How to return something from saveform.php (preferably xml I think, If i know how to do that I can apply it in             otherlocations)
3. How to handle the xml return with javascript

Thanks for your help