Do it! It's worth it. My parents dog wasn't chipped when he went missing. It may not have gotten him back, as we suspect he became some coyote's dinner, but it would have been nice to at least be able to rule out one more avenue.
Even if you are on the right track, you will still get run over if you just sit there. (Will Rogers)
I just had my dog chipped and we are using homeagain. It seems like a good company. I have already received lost dog notices in my area. They also notify any area rescues, shelters, and vets if a dog is lost.