They sound like white flies. I'll bet you could find out more by going to the pests and disease forums on here. If that's what they are, your plants will start suffering from them soon.

Probably fungun gnats. Whiteflies are not soil-dwelling. Fungus gnats lay their eggs on the soil. The larvae that hatch feed on algae and fungus in the soil, sometimes on plant roots. When mature, the adults emerge and fly around.

They can be an indicator of overwatering, which encourages algae growth. Try to let the soil surface dry between waterings. You can also use the microbial pesticide called gnatrol which contains Bacillus thuringiensis v. israelensis.

I agree, fungus gnats.