Google gives a taste of Honeycomb 3.0 with a preview of its Android 3.0 Preview SDK. Larry Dignan has more in his blog.
Android 3.0 is focused on giving better performance to devices with larger screens - tablets. It offers a new virtual and “holographic” UI design, as well as a content-focused interaction model. According to Google it offers "refined multitasking, rich notifications, Home screen customization, widgets, and more."