iPod Car Power Supply

What do folks use for this?

I use a Belkin. The problem I'm running into is that I get electronic noise (interference) from the power supply when I plug into my car's mini-stereo aux jack. So I find myself having to run on battery power or withstand lots of scratchy electric noise.

Do any power supply packages not have this problem? Or perhaps *I* am the idiot and there are ways I could eliminate the noise?

Thanks!