I have a RadioShack 2.4GHz A/V sender that I bought this year which works flawlessly (no interference at all) - EXCEPT that I must unplug my 2.4GHz Panasonic cordless phone's main base unit in order to not get interference. After talking to RadioShack's & Panasonic's tech support, I learned that there is no way around that issue because the two devices use the same frequency range. Panasonic said, however, that any 5.8GHz (or above) cordless phone should work fine with my video sender.
My workaround: I have an old cordless phone I keep by my bed and which causes no interference with my video sender. So at night when I want to use the video sender to watch the higher-end cable channels on my bedroom TV, I just unplug my Panasonic phone unit's base (I can keep the extra handset charging in its cradle base plugged in with no problem), and plug the phone's base unit back in first thing in the morning. Next cordless phone I buy will be the newer 5.8GHz model--when they go on sale.
P.S. I did have to do some experimenting at the beginning to get the video sender to work properly. I found that I must use the coax cable connector rather than the RCA-style video jack when connecting it to my OLD (but still great picture!) Sony Trinitron TV. But now it works great.