iPad2 and iTunes help

[Offshore1]

Bought iPad 2 on Saturday, hooked up to computer w/ latest version of iTunes and set up as new iPad and registered it w/ Apple. Been using all this time.

This morning I figure it is time to back it up and maybe put some pics and music on it.
Plug it into iTunes, and I get "set up your iPad" message again.

Anyone know how to get around this screen and get it to allow me to add pics and music?

Setting it up again is easy enough, but I don't want to lose what I already have.

Thanks in advance.