Also to Dave, I posted a model similar to the one I use earlier, but here's my actual water change pump. I can't tell you how long and well this little sucker has served me. As you can see it's a little more compact than that clunky similar model, making it ideal for water change purposes.
And to KronikGrower,
All I do to get my fluid out is shove this down deep so that the rim of the suction point is touching the lowest point of the tub bottom. I use this same pump with a short hose to reintroduce my fresh solution. You get the idea.
Plug it in, and that's it! Stupid easy, huh?