1 GB or 2 GB Clip for audiobooks and podcasts?

Impact DC Car Power Adapter for USB Powered Devices – would this work for plugging the Clip into the cigarette lighter? It puts out 5V/500mA - is that safe for the Clip? Are there better alternatives?  I would like to keep from running down the battery while playing it in the car.  I’d also like to get an AC adapter/charger, so I can charge it in the house without connecting it to the computer - what do I need to get?  Thanks for all the help.