There are several web references on related work. Note the availability of the hardware and software for ADS-B is only part of the solution (somewhat similar to having a modem and plumbing of the internet). The rest of the solution is the development of applications and operational concepts (roughly similar to having a web browser and web servers & content and e-mail and what not). Initial evaluations need also to be followed by extensive simulation, analysis and improvement, then implementation of the improvements, creation of standards, certification and operational approval. (Is that enough background before the web addresses!)
http://www.caasd.org/cdti has draft operational concepts and other useful information as well as links to other sites (incl. FAA Tech Center).
http://www.ads-b.com is a Cargo Airline Association site, describing what they (and FAA Safe Flight 21) are doing and with many useful links.
Also look at
http://www.faa.gov/safeflight21/
for the Ohio Valley and Alaska Capstone efforts as well as some others (Follow Links from there).
http://blinder.lfv.se/ans/card/nean.htm and
http://www.aatl.net/projects_frame.htm
are good sites for keeping track of the European trial activities.
NASA, NLR (The Netherlands) and Eurocontrol are involved in the Operational concept development and Human Factors evaluations for some of the upcoming appolications.
As for manufacturers, a UPS subsidiary (UPS AT) has fielded equipment that is being operationally evaulated (some are their own design, some bought from others). The major manufacturers are making provisions in their latest equipment (including Transponder and TCAS) for ADS-B transmit and receive functions and are awaiting the publication of standards for creating a certification basis. The RTCA standards for the 1090MHz ADS-B (transmit/receive) are close to publication. The VDL-Mode 4 draft standard proposal is in review and is expected to be published soon.
[This message has been edited by Narada (edited 27 August 2000).]