We originally planned to run wires from the bedroom to living room, but my spouse suggested "making ooma wireless" so we don't have to plug anything into it.
Our current setup is DSL modem/wireless router (all in one) > ooma Both computers use the wireless network to connect to the internet and we haven't had problems with talking while someone else is online.
Basically we want to replace the ethernet cable that connects ooma to the DSL modem so we don't have to run wires to put the hub where we want it.
Before we buy a wireless ethernet bridge, I want to verify that we're getting the right device and that by sending the signals wirelessly won't affect our QoS.
With that said ...
I personally have tried this out, and used a wireless bridge on my Telo system. I had the same concerns as you did about whether it would work well, so I bought a refurbished bridge on ebay at around $50 to try it out. It worked great for me, and I tested it for a week continuously. The reason I wanted it was to be able to use Ooma while traveling internationally for a couple of months. I knew that several places would only have wifi, so I wanted to be able to use Ooma whether I had wires or wireless internet available.
The bridge worked on my travels, but using a "public or shared" wifi signal adds even MORE variability, so the results weren't always stable, but were still good.
Your situation is a little different since you want wireless to be your permanent solution. My personal preference would be to stick with a wired connection, if you can. I ran A LOT of cat5 throughout my house for everything networked, because wired connections are simply more stable. But, if you find either cheap bridge or one that you can try and return, give it a try.
That was the long answer ... the short answer ... it works, but it's not preferred (and not recommended)
Ooma Hardware: Hub/Scout(2) and Telo
That being said you could get a WRT54GL ($60 new), flash it with Tomato, and set it up as an Ethernet bridge.
I did this for my PS3 (which is on the opposite side/opposite floor of the AP in a 2500sq^2 house), and my throughput went from 5 - 8Mbps (using PS3 wireless) to 20Mbps+, and pings went from ~70ms to ~20ms. What I'm saying is you should be ok (although YMMV.)