1Password is a password storage app, mainly for the desktop (where it costs $29) , which synchronizes via the cloud to multiple free mobile clients, including iPhone, iPad, Android and now Windows Phone 7.
The software uses Dropbox accounts for their free online storage, and everything is secured by strong encryption.
On Windows Phone 7 the main competitor would be Illium’s eWallet, which at the moment does not sync with a desktop component where data entry is a lot easier, making 1Password the clear winner.
Read more about the app at Agile’s website here and find the free app in Marketplace here.