Web Header Viewer
A site's header is pretty much the first thing a browser or search engine's bot sees when visiting a site, and as such, it's an important thing to get right. Use the HTTP Header Viewer to make sure you've done so.
The tool's easy enough to use. Give it a URL, and it'll show you the exact HTTP headers that are on display. This should then allow you to monitor any redirects and check that everything's in working order.