Instructions:

1. Enter a graph marked up in DOT Language
2. Select an appropriate graphing engine (Scroll to the section titled 'Roadmap' for a description of the different engines available)
3. Click "Make me a graph!"

To save a graph locally, just right click and select "Save picture" or "Save image as..." depending on your preferred browser.

About Erdos:
Erdos is a simple javascript interface into the Google Chart Graphviz API. For more information see: the main site.