Why are my iOS devices slow to ping / download / upload?

Hi everyone:

I just moved to a new home, and found that after a day of excellent wireless service, I was suddenly sluggish.

I chalked this up to the new ISP, but found that I was only encountering sluggish speeds on my iOS devices (an iPhone 4S and 3rd generation iPad). My Macbook Pro (mid-2008) is positively flying -- I have 22 MBPS service, but am clocking well above 30 in my tests. My iOS devices, meanwhile, max out at 1 most of the time.

I am using an Airport Extreme in my office. I have an Express in our living room, but I'm only using it to supply Ethernet to our TiVo.

I do not find that the service improves when I move about the house. If I'm in the same room as the router with my iPhone or iPad, I'm not seeing a speed difference.

I've reset the router, as well as resetting the network settings on each iOS device. I will occasionally see a speed bump to 5 MBPS, but it's rare and short-lived. I am not noticing a trend in those rare speed bumps. They occur throughout the house.

I've hit a wall in that I don't see exactly what my next step is in terms of troubleshooting. Any thoughts on what I might try?

Best,

John