I created a robots.txt file and a sitemap.xml file. Do they just need to exist in the web root, or do they need to be linked somehow?

www.brightfusehosting.com/robots.txt
www.brightfusehosting.com/sitemap.xml

Just upload them at root levels..

They are already uploaded to the correct locations. You can use Google and MSN webmaster tools to track the level of SEO, keywords where you get the search from, keywords where your URL was clicked, etc.