Cloud app to handle grocery list over Android/iPhone & Windows/Mac I am looking for an app or service that would let two different users view &amp; update a shared shopping list from an Android phone (Galaxy Nexus running 4.1), iPhone 4S and laptops (Windows and Mac).

I was originally planning on using a text file via Dropbox, but I don't think that can be updated on the iPhone (maybe I am wrong).

Any other ideas?
Google Drive (née Google Docs).

Just create a simple document. There's a Google Drive app for Android, of course, but even without the mobile web version works pretty well (which I'd expect you'd use with the iPhone). Windows and Mac can use the desktop browser version of the web app.