The micro-USB seems to be a new (but not universal, alas) standard for cell phones, so having it on the Kindle 2 should work to our advantage:
http://news.cnet.com/universal-cell-...s-coming-soon/
Unfortunately, Apple doesn't seem to be going with the herd on this.
It is claimed that the micro-USB has a much longer lifespan (in terms of plugging it in and unplugging it) than the mini-USB connector:
http://www.tech-faq.com/micro-usb.shtml
I first encountered this on my Palm Pre last Summer, and I must admit I was annoyed that it was different than the mini-USB that's been used on most of my devices lately, but it should be advantageous in the long run. For now, I have three small electronic devices that use mini-USB, and two that use micro-USB, and that is a pain!