The traditional approach is to use a long stick, catch a bit of blanket weed and then twist - you'll get MASSES out in one go, but you'll need to repeat regularly to keep the pond clear unless you solve the issue of WHY you got blanketweed in the 1st place.
Have you tried barley straw? You can get it in most garden/acquatic centres now. As it breaks down it kills of the blanket weed till you have lovely clear water. I would try and get as much out as you can first, as Tangle suggests. Make sure you leave it by the side of the pond for a day or two though so creatures living in the weed can get back into the water. Then put it in your compost bin, lovely!