Status_203 - 11:09 am on Oct 26, 2009 (gmt 0)

One possibility is a cookie check redirect on entry to the site.

If there is no sid present on a page request then serve a cookie with a new sid in it and redirect to a page that checks for that cookie and sid (when I do this I also pass the sid and the original page in the url so I can confirm that the sid, if present, is correct, and can then redirect back to the requested page.). Then run your appending-sid-to-links-in-the-page routine in such a way that it doesn't actually append the sid if the sid is being passed in in the cookie.

Of course, search engines (and other bots) will be making a fresh "entry" on each request pushing up the load on your hosting. So you might also want to look into whitelisting SE spiders (and bypassing sessions entirely for them), and maybe even look into into bot blocking if you have a popular/large site.