I just tried TwonkyServer. It is a pretty Cool App.
TwonkyMedia Digital Home Forum • View topic - TwonkyServer Mobile is now available to all Android users!
It does NOT stream video from your Droid.
It DOES make the Droid a Network Sharing Device, and makes all of your Droid Media (Music, Pictures, Video) available to other Sharing devices on your network, such as Computers, PS3, XBox360, and even some newer TV's that have Media Sharing capability built in.
...and it works over Wi-Fi.
While it does NOT meet the specific requirements of the OP (to stream video to a TV over an attached cable), it is a pretty cool way to access all of your Droid Media from other Network Devices over a Wi-Fi connection.