Probably aphids.

Spray your plants (especially the undersides of the leaves) with a soapy water solution. You can buy an insecticidal soap at your local garden center. It is organic as far as I know.

Good luck,

Gary

The insecticidal soap is an excellent treatment for many pests, and very good advice from Gary. I recently found a source for an industrial strength organic soap that is reported to not only repel white flies, but fruit flies as well. I'll know in a couple of months whether or not it lives up to it's billing.

What do these little critters do? Do they crawl around, fly, or in any other way move about? If so, they aren't aphids.