Is it Just Me, or is the Internet Slowing Down?

I have recently noticed that my iPhone, once slow, is downright glacial post-mass-iPad adoption in the greater NYC area. Daniel Altman, among others, has also noticed the AT&T network slowdown. But it’s not just the iPhone–internet connections I’ve used in both New York and New Jersey seem slower than usual. Is there any good, reliably updated data on network speeds out there? I seem to recall that Google was releasing some sort of monitoring software, and CNET offers a service, but I was wondering if there’s some central observatory. Maybe this is how the machine’s stoppage starts.