Right click on the windows desktop. Select Properties, settings, Advanced. There should be dual head/clone/dual view or something like that (depending on your video card)
It's really annoying you have to switch them over. When the TV is primary, LCD is secondary there is no movie image on the laptop screen. And vice versa. You only need to do this for movies though- for normal desktop use it'll output the same.
Just use a s-video to s-video cable. If you want high quality audio, use digital audio out from your laptop (if it's got one) or purchase one of these (only outputs 2 channel) I've got one myself, cos the headphone output sound awful..
http://cgi.ebay.co.uk/ws/eBayISAPI.d...&category=4786