Baby monitor with portable child unit?

[fanghsing]

Does anyone have a recommendation for a baby monitor with a portable child unit? I have a great video monitor for DS's crib, but sometimes I just want to put a monitor next to him if he falls asleep in his car seat or is taking a nap on my bed, etc. I'd love to have just a simple audio monitor that I can move around the house -- unplugging and re-setting up the video monitor is a pain! I bought the Safety 1st Glow and Gro but it has a constant stream of static and it's hard to hear tiny burbles when there's a roar of static coming from the parent unit. Any ideas? Thanks!