Scribble Maps is a great Google Maps mashup that lets you draw directly on a Google Map, save your scribblings and even export a kml or jpg or gpx of your work. Scribble Maps now also lets you draw on a map of the night sky. So yes - now you can create your own constellations.
Here's mine, The Alligator,
Other Google Sky Mashups
- Star Viewer
- SIMBAD Astronomical Database and Google Sky
- HeyWhat'sThat Cosmic Visibility
- Hertszptung-Russell Diagram