Vuze has issued a report (First Results from Vuze Network Monitoring Tool) analyzing the network management tactics of ISPs.
Here's an excerpt from the report:
We believe that there is sufficient data to suggest that network management practices that "throttle" internet traffic are widespread. At a minimum, more investigation is required to determine whether these resets are happening in the ordinary course of business or whether they represent the kind of throttling practices which target specific applications and/or protocols, harming the consumer experience and stifling innovation.
Read more about it at "Study: All Major Broadband Providers Disrupt P2P," "U.S. Senate Committee Tackles Net Neutrality Today," and "Vuze Says Some ISPs Abuse TCP Resets; Data Not That Clearcut."