Aphid Attack!

So a week or two ago, I went out to the garden to harvest some more lettuce. Tucked into the leaves, I found a LOT of bugs. Ack! I didn't know what they were, so I took a picture. I showed it to Tom and he googled--low and behold, I have aphids. Crap. I should have known what they were--I did work at a greenhouse after all. All this time I thought I knew what aphids look like; I wasn't even close. Doh.

I have since posted a request on freecycle for ladybugs. No luck. I had one response suggesting I sprinkle seven dust which I don't consider an option. I have also read a couple other blog posts that say Home Depot sells them-not in this neck of the woods! I did some more investigating today and found that I can probably control them with jets of water and sprays of soapy water. So far it seems that the little buggers are not harming the lettuce, just freaking me out a little.