Mine vacs through the pump via the skimmer. I just disconnect the return line and let it drain onto the ground as I vacuum w/ the pump on.

If you don't have that set up, you can adapt a regular vacuum hose attached to a vacuum head by using a rubber coupling from your local hardware store. Just attach one side to the vacuum hose and the other to the nipple port where your skimmer attaches at the pool wall.

Make sure to get all the air out of the hose before you start to vacuum or you'll vapor lock the pump. I used to hold the hose near the port with the pump running and move it away as soon as I heard it start sucking bubbles. Those bubbles will come out into the water and dissipate. Repeat the procedure until the hose is clear of air. It's a pain, but it gets the crud off the bottom of the pool.

Since I've kept the algae out of the pool, I've not had any problems with the normal vacuum system for the larger items and my water is crystal clear.