If you are with Virgin media and going to use the internet to any great extent during the peak hours (daylight hours 10am-9pm, I know it sucks) and don't want to be throttled after the threshold level (details here http://allyours.virginmedia.com/html/internet/traffic.html)
has been met there is a way to avoid it.
If you phone them up after being throttled they will unthrottle you and say next time try and determine your downloads. However just phone them every time they throttle you and they just continue to unthrottle you. I know it isn't the ideal system especially on a what is meant to be an *unlimited* package but it might help some people that just want to finish downloading something fairly quickly and not wait for the throttle to end before finishing.
Until you can get the unthrottled 50mb package which is not available in East Belfast yet :(