I need some help, I am new to the high def world but I just bought a LNT4661 Samsung tv and Denon receiver 1508 I connected all of my speakers center, 2 front and 2 back speakers . I connnected my blu ray DVD player and my cable TV with HDMI cables and connected both to my TV with one HDMI cable.
I ran a optical connection from my cable vision HD cablebox audio out to the receiver and did the same to the Blu ray.

The problem is I get a picture and sound on my TV but the new Denon has no sound. Is there a set up internally that I have not done and if so please tell me what to do . I must have missed something or pushed something I should not have.

The 1508 is a HDMI pass through device, so optical is the correct way to go. I don't have the 1508, but most likely you have to go into the setup menu and assign the optical inputs to a source. I have a 3808, so the audio setup many not be the same.

Source Select > Source > Assign > Digital > Input #

Your manual should detail the method.