you would do it in the same way as you set up two iPods or iPhone or iTouch, in iTunes.
Each device is unique and can have it's own choice of content.
You might want to prevent auto syncing until you sort it out though.
I am planning on purchasing an iPad. I already have an 80GB iPod where I keep my music library. Is there a way to set up different syncs for the two? I am thinking I want to sync my videos, and a portion of my music to the iPad, and sync the entire music library to the iPod. My entire music library would fill up the iPad, and not be much use when I exercise, etc.