If you are a Boxee user, check out the boxee iPhone remote app and see if it suits your needs:

• the boxee remote app has two modes: Gesture and Buttons
• in the Gesture mode you need to hold down your thumb and move it around in order to navigate.
• clicking on the boxee logo acts as Select/Play/Pause
• dragging the boxee logo to the edges of the screen will act as a continuous up/down/left/right
• clicking in an input field will open up the iPhone Qwerty keyboard and will enable you to easily enter text
• the app works over WiFi, so make sure the WiFi on your iPhone is turned on

More info: Boxee remote app (iTune link) | Video