I moved my fish from my 29 gallon to a 72 gallon this last weekend. I lowered the water by about ten gallons. I then moved (dragged the stand and tank) the tank over by my 72 gallon and as I caught them I transfered them into the new tank. I used an 8x8 net I picked up at petco for $4.00.
I used a bucket with a lid filled with water from my 10 gallon to move them to my 29, that way they had room to swim, and i just was able to put them all in very easily, with minimum spill and stress.