iPhone: If you're looking for a lightweight and simple way to monitor your Raspberry Pi, Command Pi is a utility that allows you to monitor your Pi's memory usage, temperature, and more right from your iPhone.
To use Command Pi, you'll just need to make sure SSH is turned on for your Raspberry Pi, then enter the IP address and login to sync it up. Once that's set up, Command Pi can shutdown the Pi, restart it, or if you're running XBMC, restart that. You'll also see a few stats like CPU usage, memory, temperature, and MHz. The single screen in the screenshot above is all you get, but it's all surprisingly useful. A few users report crashing with the app in the iTunes reviews, but I didn't have any problems with it on an iPhone 5s.
Command Pi (99¢) | iTunes App Store