There's no PinMeTo app (yet), but there's a quick way to set up something almost-as-good on your iPhone: a home screen icon that will take you directly to the mobile PinMeTo Places site. Plus, this uses way less storage space on your phone than an app, and doesn't need updating. Here's how to get it:
Launch "Safari" (this has to be done through Safari, even if you normally use another browser)
Go to places.pinmeto.com and log into your account
Tap the arrow-coming-out-of-box icon at the bottom of the screen
Tap "Add to Home Screen"
Enter a name for the shortcut, then tap "Add"
Swoosh! The shortcut is now on your home screen. You'll need to log in again when you use it for the first time, then you'll be good to go with your not-quite-app!