1) Throw away your microwave. Okay, so this isn't an attractive option! But you may have a particularly leaky oven.
2) Move your AP further away from your microwave oven. If the oven isn't leaking much signal, additional distance may reduce interference to an acceptable level.
3) Throw away your 802.11b WLAN devices and buy new 802.11a devices. 802.11a operates in the 5 GHz frequency and is therefore unaffected by common household interference sources like microwave ovens, 2.4 GHz cordless phones, and Bluetooth.
4) Assign your 802.11b/g devices to channel 1, which is the farthest you can get from the center frequency used by household microwave ovens. To learn more about why this might help, read this paper by researchers at Tamkang University in Taiwan. Some interference is still likely, but you may be able to minimize its impact.
This was first published in May 2003