Desktop password manager LogOnce has released a new way for users of the iPhone and iPod Touch to skip having to enter usernames and passwords on sites that require them. You can log in to any site for which you've saved a password just by opening up a special bookmark that plugs in your log-in credentials for you.
There's no software to install and nothing to remember. You can also wipe out any access, just in case you manage to lose your phone, or it gets stolen.
It's devilishly simple, and it works, though the setup is a bit tedious. You must first register with the site, then plug in all your usernames and passwords from various sites, then make sure you're logged into the LogOnce site via your device. After that, it's simply a matter of summoning up the bookmarklet shortcut when you're on the log-in screen at any given site where your registered.
To help make things a bit simpler, you can do all the password management on your PC, if you're willing to download the software version. It syncs up all the log-ins you've provisioned to the your account, so you can access them on the device. In case it's stolen, you simply change out your master password, which will keep any would-be identity thief from being able to access your information.
A far simpler solution, if you're willing to install something on your iPhone or iPod Touch, is 1Password. It's one of my favorites because it gives you far greater control over the fields you can enter, and it blends the management with browsing in the same space, which can be helpful, if you want to make changes on the fly.