i have moved tanks several times in my life, 6g to 55g so far. when i have to do it, i use 10g rubbermaid tubs. they are about $3 at wal-mart, and worth much more. use a small hose/syphon or whatever to transfer enough water into the tub to cover the fish, about 1/3 to 1/2. keep in mind that 1 gallon of water is a little over 8lbs. make sure you can lift it easily.
drain as much water out as possible - this will make netting the fish much easier. place the other items from the tank into a garbage bag, heaviest items on the bottom. if the heater is glass, you can put it back in the tank during transport to avoid breakage. take it out while catching the fish. once all the fish are in the tub, put the lid on it to prevent stress - they get scared if the lid is off and you are standing over them. drain the tank as much as possible, and move it out to the car. if there is a lot of gravel, ask someone to help you with it. shouldn't be too bad though. then move the garbage bag of decor and filter out to the car, and the fish last. when you get home, bring the fish in first to avoid high temps from sitting in the car. this will be the tricky part - acclimating the fish to new water.
the best way to do this would be to set up a separate bucket (or the tank) with new, dechlorinated tap water. using a separate container will be easier because you don't have to add dechor everytime you add water to the bucket that the fish are in. okay, so you have your treated 'new' water - add a couple cups of it at a time to the fish tub, like every 15-20 minutes for an hour or so. make sure the new water is within a few degrees of the fish water to prevent temperature shock. now that the fish have gotten a feeling for the new water, start taking water out of the tub and putting it into the tank, as much as you can remove easily and still leave water for the fish. catch the fish, put them back into the tank, and then add the rest of the water left in the tub. by this time they are used to the new water that you have acclimated them too, and you can fill the tank the rest of the way with new water. using the garbage bag keeps the decorations and filter media wet, so little to no bacteria is lost during the transfer.
I just used this method today while moving my 55 across to the other side of the room. it works very well. if you have the extra cash available, get more rubbermaid tubs! this way the other stuff (plants, decorations, filter media) can all go in a a separate bucket than the fish but still stay submerged, and i think a tub is easier to carry than the garbage bag, which may tear.
