The FCC recently reminded people (on 5/28) in the United States that there has been a change in spectrum allocation to avoid interference. On June 12, 2010, wireless microphones and monitors will no longer be able to be used in the 700 MHz band (specifically698 to 806 MHz). Here is the PDF on the FCC website.
What this means, is those individuals/groups who use wireless microphones for audio capture for video, screencapture, or podcasting, in the above bandwidth will start to receive noise and non-ideal audio as new 4G consumer devices are deployed in proximity to the wireless microphone.
The solution for the vodcasters/screencasters/podcasters is to either replace the wireless microphone or work with the equipment manufacturer to get the wireless radio inside the transmitter & receiver changed out to operate on a frequency outside the 700 MHz band. Some manufacturers have a trade-in or rebate programs to help people with this change.
Here is another helpful link on the FCC website which lists known wireless microphones in the 700 MHz band.
Now, if by chance you live on a Indian reservation away from any mobile or cellular phone service, your wireless microphone should work just fine after June 12, 2010. 🙂