Another company is peddling similar technology to the Applied Digital Solutions ID Chip mentioned below.

Here's an editorial by David Coursey for CNET Asia:
An implanted ID chip? Makes my skin crawl...

The concept of a national identity card--something you'd carry to use for matching with your fingerprint or retinal scan--gains a new dimension with implant technology. Or perhaps the chips could be implanted at birth as a sort of digital birth certificate.

Thinking about such prospects reminds me of three essential aspects of any new invention: The first is that technology is amoral, even when there is a temptation to consider it immoral, instead. Second, it's pretty hard to keep technology under wraps: If something is technologically possible, somebody is going to do it. And, finally, if something is created, it will probably be both used and abused.

I hope that VeriChip and its ilk--which have great potential to help people--will find their way into the hands of people who are well-intentioned and smart in equal parts. But I am not naive, either. This is what the ongoing privacy debate is about--and the VeriChip gives us another good reason to pay close attention to it.