Microsoft CodePlex has released a GMail Notifier for Windows 7.
This is a simple application that notifies you when you receive new email in your Google GMail account.
c2i GMail Notifier is fully Microsoft Windows 7 compliant and works only on Windows 7.
If you want to get GMail to your Desktop, use GMail for Windows 7. GMail for Windows 7 is a free tool which brings GMail to your Windows desktop, using the new features of Windows 7. The application does not require any installation and you can directly run it directly after giving your GMail credentials. Even though this application is called GMail for Windows 7, it will run in other versions of Windows too.