Wet/Dry shop vac.. Done...
Get a bucket head from home depot for $10, works awesome!!
i've used a wet dry before but it can be a little messy. I recently bought a cannister filter to do it. It's pretty easy as I just put the outlet back into a filter sock so I don't have to change the water out.
I use a maxijet 900 with a piece of hose attached to the inlet side and one on the outlet side. It works well as long as it is just detritus you are sucking out, small sand grains will go through ok most of the time but I wouldn't try and suck more than a few grains through there. To start the suction you may have to prime the pump by sucking some water through the suction side until it hits the pump impeller, then it will take off on its own.