Here's my AVR ISP adapter in action:
It's connected up to an ATTiny85 that's programmed and wired at the moment as my reflow oven controller.
You can find the board in my OSH Park profile. I'm not going to offer them for sale other than that, because they're the same thing as the SparkFun ISP adapter, and if you want just one, they sell theirs for only 95¢. The big difference, though, is shipping - you'd have to pay for shipping from SparkFun, but in principle, you could order a bunch more stuff to make up for that. You can get free shipping from OSH Park, and they're only 93.3¢ each, but you need to order them 3 at a time.