It's a nice compromise between swimming and actually getting completely wet - more like water aerobics, yeah. The program I'm using is the one Purna mentioned, the Pfitz program at http://pfitzinger.com/labreports/water.shtml which is mostly intervals - alternating easy and hard - and it's a good workout. I'm finding it way more enjoyable than treadmill running, which is so deadly boring I have a hard time doing it for more than 20 minutes - I managed an hour of pool running no problem today!