Can I build a solar heater for an above ground pool?

Residential Solar Power Question

I have an above ground pool that the kids love to play in, I don't want to spend money on heating it .

I am wondering whether I can build some sort of solar heater for my pool. Do I need to buy some sort of solar power kit or is this something I can build myself?

I have lots of power tools and the pool sits in an area where it does get lots of sunshine all day so I am sure that using the sun to heat the pool is a good idea, I am just wondering how to do it or what sort of kit to buy.