Not sure about your TV situation, but I use Jaadu VNC on my iPhone to access my HTPC (with UltraVNC installed). You can use it wherever you have data access (3G or Wifi preferred). Jaadu RDP works as well if you have a version of Windows with Remote Desktop Connection. However, using VNC allows you to control the computer with it displayed on the TV using the iPhone as a mouse and keyboard. With RDP it will disconnect the user's session on the TV and display the logon screen. One advantage of RDP is that it will transport the PC audio to the iPhone, where VNC does not.