From Mike Ward:
Tweetz is a Windows Sidebar gadget. It stays on your desktop where it's always available. And if you're a fan of Windows 7's Aero Peek, you're going to love Tweetz. Simply move your mouse over the "Show Desktop" bar at any time to reveal your gadgets, including Tweetz, and read your tweets. Tweetz also respects the gadget guidelines. The docked version (pictured above) is 130 pixels wide and plays with other "docked" gadgets correctly. Want more realestate? No problem, the undocked version is wider.