1Password app for iPhone
Syncs using dropbox (also awesome), so that my iPhone and iPad are both always up to date. There is a desktop app as well, (originally for the mac), although I don’t have it.
This password app allows me to keep all my passwords and even some credit card information protected, but available at any time. The iPhone app allows access via a four number password, which makes it very convenient for quick access.
I don’t know how I’d manage without 1Password.