If you’re having trouble with iPlayer on a mobile device over WiFi, this may be of some help:
I recently installed a Netgear DG834 ADSL 2+ modem router. It works beautifully.
My other new toy is a T-Mobile Pulse Android phone. A lovely bit of kit for not very much money.
Trying the excellent beebPlayer application (an iPlayer client for Android) I found that quality was far worse on WiFi than on 3G. Surely that can’t be right?
To cut a long story short, the DG834 has a feature called Port Scan and DOS Protection, which as it turns out interprets the incoming RTSP packets as a DOS attack and drops most of them. Switching the feature off (under Advanced / WAN Setup) makes it all work perfectly.