Our next door neighbors just had a baby. Since they brought him home, we have been noticing interference on our baby monitor. We either here static or sound from their baby monitor transmitter. It seems that they have either the same model baby monitor, or one that transmits over the same frequencies.
It got me thinking, that we have a relatively robust wireless signals going around our house. Our 802.11g network is very robust, even though there are several other networks nearby. Since 802.11 chips are pretty cheap, it would be great if someone would come out with baby monitors that use 802.11 as the transmission protocol. All that it would have to do is broadcast the audio stream on the subnet.
Both the transmitter and receiver would probably need to have a USB port, so they could be configured to use specific wireless network settings.