I have an HDTV (Westinghouse 46" LED 120 Hz) and a Sony S.A.W 3-channel stereo w/ subwoofer (150 watts I think?), anywho I'm stumped on how I can connect it to my HDTV so the sound will come out of them when I'm watching TV/ movies/playing Xbox.
The Red/Yellow connections on both will give you sound out of the speakers. Standard RCA cable.
Then in the TV menu you will likely need to disable the internal speakers on the TV, or set some other option to External Audio Device.
Also make sure you turn up the volume on the TV all the way, then adjust the volume to your liking on the speaker system. Having the volume high on the speaker system and low on the TV itself will result in poor sound quality and lots of noise.