Cool moving background navigation... HOW????

[principe]

I just found this site and my jaw dropped! Does anyone know how it's done?

http://www.unit9.com/moon/

[atulsc]

what exactly u wanted know about this..it's better if u r little more specific...anyway... I may not able to help u out with this cuz it looks real pro work.. if u r asking about the drawing...i think they drew it with pencil then scanned them in.. cuz it looks very realistic.. but other effects look quite simple ..they r just moving around.. it's the look n feel thats making it look so different...u need to work hard on the drawing.. not much on programming..