Even though they're tiny, likely a picture or two will help us. Any chance of posting pictures?

Botanicat, I hope you don't mind my posting a picture here because I might have what you have (and then some!). I have the white insects too, which look a bit like tiny white mosquitoes with legs almost invisible to the bare eye. But--I also have the little pink insects with those white ones. These are on the underside of leaves, and I do have some curling of leaves near the base of the tomato where I found the insects.

{{gwi:1294777}}

The picture looks like what I've got. Is this a stage of white fly infestation?

Nope. They're aphids. The pick ones are alive & feeding; the white ones are cast off skins. Brush off, wash off, or squish.

But realize that the elongated fellow towards the right is a beneficial which helps you limit aphids. (Counting from the right hand edge, it's the 2nd one in.)

OK, Jean! Thank you. I think I might remove a few of the smaller leaves which are heavily infested, hose the rest. What is the "good guy?"

The tomatoes are near the rose bushes, so the aphids probably migrated from the roses.

I always have aphids on my tomatoes. Without using chemicals, there's only so much I'm able to do. But I hose them off/ use garlic spray to take care of most of them. One of the most annoying pests ever. But easily squishable!

Kim