I am looking to purchase a Speaker docking system for an iPad2, I also want to be able to use a 6th generation iPod Nano with the same dock connection.
Is the connection on the iPad 2 the same as the connection on the iPod Nano?
The iPod Nano 6th gen uses a 32 pin connector, the same found on iPod classic, iPhones, and more importantly in your case the iPad/2 you will find all the specficatons for docks on the Apple support website. Although it doesn't mention the 6th gen Nano.
This omission makes things slightly unclear however if you check out the product description for the Apple dock connector to USB cable you will see it is compatible with the 6th Gen iPod nano.