VNC2Go is a VNC client (viewer) that runs on MIDP-enabled devices. It lets you control any desktop server running a VNC service, from any mobile device that supports Java Midlets, such as mobile phones and PDAs.
Needless to say, a mobile phone is not the friendliest interface to remote control a desktop computer. However, when you need it, you need it. You can use VNC2Go to send yourself a document you forgot at home, restart a service that crashed, check for an expected mail message, look up a phone number you have at home, etc.
Hopefully, within a couple of years the mobile phone interface will be more mature for such advanced applications, with bigger and better resolution screens and simpler input mechanisms. VNC2Go has several input modes, to try and compensate for the not-so-friendly phone interfaces.