So everywhere I read I see VAG-COM this and VAG-COM made coffee and some guy on some forum even claimed that VAG-COM was vagging his wife...

Anyway...what is it, why do I need it, where can I get it?
I've been on Ross-Tech's site, and almost downloaded the software but I'm sure its not as simple...do I need to buy anything? A cable?
Is it one of those plugnplay cables you connect to your laptop and then to the car's ECU and then read all error codes and delete them etc?
Cheers
Lance