At the risk of turning this into an Apache fan blog, I have to mention the handy directive I found today. Many webmasters run in to mod_rewrite at one time or another and every one of them will have at least a little trouble with it. I just came across the
RewriteLog Directive and corresponding
RewriteLogLevel Directive. You're not going to be able to turn these on with shared hosting, they can't be used in .htaccess. To set up a debugging log for mod_rewrite, you need to add them to your httpd.conf somewhere. In my case I'm working on a server at home so I added