What do you want to test out?
When you say wifi phone, I assume you mean VoIP? if so, what protocol, SIP, MGCP, skinny? What compression standards G711? G729? Do you have network hardware that supports VLans? CDP? QOS?

Even if you had all of this, what software are you intending on using to control them? and if you have this sorted, I assume you are going to get a primerate isdn line?

That aside, cisco do a nice 802.11b phone - it needs a cisco AP to work though and if I remember correctly is around $700 + gst (this is a good buy price too) - its cheaper to get a cisco ATA186 or ATA188 with 2 POTS ports and get a top of the line, state of the are cordless phone, and you will stillhave change for some beers (as in free)

Cheers

-John