TeamViewer is one most popular option for Mac, PC and now for the iPhone, that allows you to login remotely into a computer to offer assistance or to manage it.
All you have to do is to install TeamViewer on your computer, take the data that it gives you and input it into the iPhone app to gain full access to that computer.
- Both spontaneous support and remote access to unattended computers are possible
- Convenient control via multi-touch gestures: left click, right click, drag & drop, scroll wheel, zoom, change monitor
- complete keyboard incl. special keys such as Ctrl, Alt, Windows®
- reboot the remote computer
- automatically decrease the screen resolution of the remote computer
- integrated partner list – see which computer or partner is online
- trouble-free use behind firewalls and proxy servers
- highest security standards: 256 Bit AES Session Encoding, 1024 Bit RSA Key Exchange
TeamViewer Pro is available in the app store for $99.99. The Pro version is only for commercial use. If you need the app for personal use, they also provide a free version in the app store.