When I discussed Internet Lockdown habits, one of the major practices I mentioned was to kill online applications when not in use. Email and instant messaging are obvious culprits in this regard, but a web browser has even larger time wasting potential. This can be a problem when your everyday workflow involves the use of web based applications or HTML based documentation. My solution is to run these applications in a browser that strips down all potential for stumbling from your tool or reference site to other, potentially time wasting, sites.
Prism is a Mozilla labs webrunner application that strips the browser down to it's bare essentials. After installing prism, setting up a new web application simply involves specifying the URL and a name for the application and deciding where you would like the shortcut to be placed. Clicking on the new shortcut opens a completely minimal browser with no address bar or tool bar, containing your web app as if it were running normally in Firefox.
I use this approach for everything from our SourceForge installation to Google Notebook and documentation for Lua and Ant. I've found it has made an enormous psychological difference allowing me to safely use web applications without negatively affecting my focus.