We've been using Wunderlist for this. Syncs across all platforms we have - IOS, Android, PC, Blackberry. We can even use it on the Nook Color using the web browser link.
Gotta admit I'd love it if Wunderlist allowed me to scan items and thereby log in what I need, and had a by-store, by-aisle organizing feature. But those oversights are just minor inconveniences compared to all the other things it does so well.