Getting digital noise when MBP audio out is plugged into HDTV

I'm having a strange problem and there doesn't seem to much about it on the online communities. Here's the deal:

I'm plugging my MBP into my Samsung LCD HDTV via DVI out to the HDMI input on the TV. That HDMI input has a stereo RCA input for computer audio. So I'm plugging the audio into the TV via the lineout on the MBP using a mini stereo jack to stereo RCA cable. For some reason, I get super annoying digital noise. The noise is semi intermittent, but is generally loud whenever accessing files in Front Row, which is all I do. I tried several different cables, same effect.

Then, I tried listening via headphones while the computer was plugged into the TV, and there's no noise. I can also plug into to a stereo system while the MBP is plugged into the TV with no noise. The noise is only present when the audio is going into the TV.

To make it even more interesting, I was at my folks place and I had a completely different configuration:
DVI - VGA cable plugged into the back of a SONY LCD HDTV with a mini stereo cable going straight into the TV, and I get the same noise! With a completely different TV, Analog video signal (VGA) and different audio cable altogether. What can I do? Does anybody have any idea what the problem is? Thanks in advance,
Dave

does this problem occur when you are not plugged in but running on your battery?

Yes, it does, but to a slightly lesser degree.

I'm having the same problem - I've had this problem for a while now. It seems to be anything that has built in speakers has have this problem. I had this issue with a monitor, and just recently with my samsung lcd tv. I wonder if you ended up finding a solution? A while back I tried cables with more insulation; it helps, but not much.

Could be non-shielded speakers in the monitor/TV causing interference with the analog signal being carried by the cable. Only suggestion I have is to move the audio cable. Get a longer one if you have to so you can route around/keep the cable away from the built-in speakers.