WAP and Phone Interference (yes - no - maybe)

OK Techies, a question for you all.

I currently have a Linksys WAP11 (2.4GHz) AP and a 900 MHz wireless
phone in the home office. There is also a 2.4 GHz phone in the house
although the base station is in another room.

So far - no real problems that any of us notice.

Now for the next step. We now are using the Vonage VoIP service for
one of the home lines. What I would like to get is a 2-line cordless
(expandable) phone where the base station will be in the office (where
the Wap11 is also located) with one line on the PSTN and the other on
the Vonage line. We would have other remote handsets throughout the
house.

I do not want to replace the Wap11 (and PCMCI cards) yet with a 5.8GHz
wireless system and there are no 5.8GHz expandable 2-line phone
systems on the market that I can find. Based on what I have heard and
read - the range of these phones ais having problems and the makers
are working out the bugs (I hope).

I can not find any 900 MHz 2-line expandable phones on the market
which leaves me with the 2.4GHz products of which there are many to
choose.

SO - THE QUESTION:

Who is mixing WAP11 and 2.4GHz phones with the base and AP in the same
room and what are you experiencing ? Are some 2.4GHz expandable
systems better (or worse) than others for interferrence?

Thanks for your advise, comments, and thoughts . .

Bill