My goldy fry are 2 weeks old now and Im feeding them decapsulated brine shrimp eggs - when and what should I move them onto next - I do have some liqiify 3 powder to hand

They sure are growing fast!! Must be about 60 of them in a 5 gal tank - this is my forst attempt to raise fry so be gentle with me!

You are doing good, Spacebux! Those brine shrimp eggs are perfect for them so far, and I wouldn't go back to the liquifry stuff again. If you can find it online at Aquabid, microworm cultures are a great, and simple way to feed your fry as well. I had my betta fry on them for most of their baby lives, and they grew in no time at all. Go check out http://petfish.net/live.htm, they have some excellent choices for fry food.
You also can try crumbling flakes really, REALLY small and feed it to them, but I wouldn't start them on those too early in life. I believe that goldfish are best off in their lives with live or frozen foods, gel food and not too much of the pellet/flake kind of stuff. That begins early in age, and with the right food right from the start you can prevent swim bladder problems in the future....

im also bit concerned with chasnging the water as they are so small and dont want to hurt them - any ideas - i have a couple of live plants in and sponge filter - water seems ok at the moment?

I wouldn't start with any bigger water changes when they are that young. The sponge filter will do a good job in biological filtration, and when you look under your sponge filter, you will see quite a bit of accumulated waste. You can get a piece of airline tubing, and carefully change water with that, and in the process get rid of the waste thats under the sponge.
Let the water go into a bucket, so you can see if you accidentally got some fry as well,and you can put them back into the tank.
For putting new water back in, do it slowly. Have a bucket with aged, temperature and pH matched water above the fry tank, hang an airline tubing from the bucket into the tank, and let the water drip into the fry tank. The slower the better, so the fry can get used to any new water very slowly and carefully. You can tie up the airline tubing a bit, so the water goes back in the fry tank slower....

I followed exactly what Ranchugirl suggested. Using this method I haven't lost a single fry. It is very important to make the water temperature the same.

I attached a 8-12" of rigid 3/16" diameter plastic tubing to the end of the airline tubing for siphoning the debris. It makes controlling where to suck easier without getting your hands in the water. Be careful of fry near the tubing. When they see solids moving by the suction they think its food and will chase after it. Keep a finger at the other end to the tubing in the bucket just in case.

what my book recomened after the first 2 weeks was tubifex worms. what i did was got a tubifex cube and crushed it up realy tiny and passed it through a fine sieve so that we know it is small enough for the fry to eat. their growth when feeding them this astounds me. try it

im still feeding decap brine shrimp eggs - they seem to love em - getting big now!
thanks for the advice - ill post pictures when they get a bit bigger!