Eastern and Legends are the two I know.

I used Eastern once and they were fine. They're a basic low-end car service comparable to Carmel or Dial7, but with the car seat option for $5. I have a good friend who always uses Legends when traveling with his kid. He's been very happy with them.

There's also KidCarNY, but it's ridiculously expensive and I don't know anybody who's ever used it.