Any technology can be used by criminals and terrorists and the more useful it is the more the need for concern. The recent terror attacks which struck Mumbai, India are an example where the terrorists not only used Google Earth but also VoIP.
But while it may be a knee-jerk reaction to blame the technology for the acts of terror, it makes more sense to think the matter through and realize that in some cases, having this technology means there are much richer trails for law enforcement to investigate. It is just that law enforcement officials need to be looking.
The New York Times has a well-balanced article on the matter which may be of interest.