Navigation and URL rewriting in AJAX heavy page

I have an ecommerce site, that isn't up to par for what we need. It was originally developed using one main page that contains user controls for item search and catagories navigation... I have a search ascx and a catagories.aspx, that talk to a restuls.ascx through default.aspx..

Anyway, there is no navigation on this site. I've looked around at URL rewriting, but most of the material was dated. Also I'm not sure this is the best route. Most of what I'm reading on URL rewriting is to put you at a certain point in a page, as opposed to bringing back a colection of search restuls for example. I'm also seeing in some places where I think people are writing page load events to look for parameters to recreate the dynamic page.

1. Is URL rewriting the best answer?
2. If it is, would I rewrite the page load to look for parameters to trigger the search again to bring back the results? Or is there a less manual and possibly less resource heavy way of accomplishing this?

I would like to make my site more SEO but navigation is the main issue at the moment. I'm using dotnet 3.5sp1.

The option are:

• URL ROUTING within the .net framework
• URL REWRITING with IIS (i think from version 6)
• Or URL REWRITER

I recently had the same problem and I solved with URL ROUTING.

Whatever you choose, make sure you point the OLD Url (not rewritten maybe present on the SERP) to the new URL using 301 Permanent redirect, so you inform Search Engine of the new path without loosing Page Rank.