All of those apps work on the iPhone, iPod touch and iPad 2. I have them installed on each of these. The WW one syncs however the other two do not and there is some talk of them ultimately using dropbox or icloud which would be handy but not essential. iWatchr is a good one if you know your points because you can built your own data base and it does not require the internet. UVD is excellent because it has a huge online data base and I can't remember if this was available off line or not.
I hope this helps.
Should have added the WW app will store your data until you are online. This is only available to WW members however. The UVD is the closest available app I have found. I have used to the data and PP from here to create my own data base with iWatchr. If you pay $1.29 NZ this app also includes the weigh chart which is not available on the free version. All available at iTunes.
Last edited by Goanna : 06-07-2012 at 04:17 PM.