I got lucky. My phone didn't conflict. There are both in the 2.4 band, but must be on different frequencies. Sadly, you can only find this out by diving in and trying it out.
Bob
I'd like to make the shift over to wireless but have too many 2.4GHz phones in the house to change them all. What system can I get that won't conflict with the phones and vice-versa?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic