There are many applications for mobile phone which can control some part of administrating a windows PC, but this one gives you complete access to PC or windows virtual machine.
Wyse PocketCloud, provides systems administrators complete access to virtual desktops remotely through an Apple iPhone or iPod touch. It is an extension of of Microsoft Remote Desktop Protocol (RDP) 6.0 to connect and communicate with virtual or physical machines. Additionally it also supports the VMware View 3.1 connection. What’s more it is secure, PocketCloud also supports enterprise-grade security with FIPS for RDP and SSL for VMware View. All you need is iPhone OS 3.0 with 3G or Wi-Fi connection. However it does not support audio.