Check out this handwritten letter from Paul McCartney written on Hotel St George stationery! The item is part of Hard Rock International's memorabilia collection and is currently on display at the Hard Rock Cafe in Miami.
(Note that the site requires Microsoft's Silverlight 2 plug-in.)
The Hard Rock site also includes the ability to grab embed code for this item to display the letter on your website. Open the "Share" tray in the information panel on the right and copy the embed code from there.