Robs Blog: Gmail Tools & Plugins: " Gmail Tools & Plugins
Plugins and tools to make Gmail easier to use are starting to pop up on the web, here are the ones I've found so far:
Official Gmail Notifier from Google (beta) - Downloadable Windows application that alerts you when you have new Gmail messages.
GMNotifier - More configurable notifier based on .NET (Via here)
Gmail Search Extension - Search your Gmail account from the Firefox search bar
Gmail Tray - A search box for the Windows taskbar
Gmail Notifier - Firefox extension, installs an icon on your toolbar that displays the amount of new messages in your "