http://www.aprs.net/javAPRS.html A series of pages containing demonstrations of javAPRS's capabilities, as well as links to most of the other javAPRS pages I know about.
http://www.aprs.net/usa.html The Miami APRServe page, with links to various documents describing the hardware and software in more detail.
http://web.usna.navy.mil/~bruninga/aprs.html Bob Bruniga's ("The Father of APRS") site contains many pages of almost live data. A must see site to understand APRS capabilities.
http://www.aprs.net/find/ It is possible to use the APRServe network to follow individual stations in their travels. A new feature in javAPRS filters out all except specified stations. The above URL lists those pages which I have created for individuals. For example, http://www.aprs.net/find/k4hg.html shows my various stations, and http://www.aprs.net/find/w7lus.html follows the exploits of long hault trucker and long time APRSer Peter Gross. If you are on APRS and would like a page here let me know.
http://www.aprs.net/usa.html The Miami APRServe site, this page serves up data from Miami and all the other live internet servers, which is often more than 600 stations.
http://www.aprs.net/socal.html The Miami APRServe data stream, but with a special set of detail maps for Southern California.
http://www.wa4dsy.radio.org/aprs/soeast.html Dale Heatherington, WA4DSY, the first live APRS internet gate. And the site is served through an rf connection (at 56 kbaud) to the internet!
http://sboyle.slip.netcom.com/LIDSAPRS.html Live Data from San Francisco, by Steve Boyle, KD6WXD
Live Data from North New Jerseyftp://ftp.tapr.org/pub/tapr/SIG/aprssig/files/ This is the primary FTP site for APRS files. The latestest version of the Mac, Windows, DOS, and Java versions of the program are available here, as well as the largest collection of maps for all platforms.
http://www.kcaprs.org The Kansas City APRS Group's site is one of the more complete sites for APRS info.
http://aprs.rutgers.edu Run by the Sprouls, containing the most up-to-date documentation on Mac/WinAPRS, and also has an FTP server that contains latest Mac/WinAPRS programs and lots of maps.
http://www.aprs.net/vm The APRS Virtual Meeting...a site with a number of different how-to's, presentations, and APRS documentation.
http://www.peel.com Canadian APRS support site containing latest APRS releases, Canadian maps and support files. Also live javAPRS site for the southern Ontario area. System also has an online BBS style message conference system where guests can exchange thoughts, ideas or list items in the Buy & Sell area..http://www.geocities.com/CapeCanaveral/Lab/2809 Northern Illinois APRS Network
KD4RDB's APRS Page A good page with introductory information about APRS.
Commercial Sites
Kantronics TNCs http://www.kantronics.com/catalog
PacComm TNCs http://www.paccomm.com/main.html#Amateur
MFJ TNCs http://www.mfjenterprises.com/mfj/packradio/control.html
Peet Brothers weather stations http://www.peetbros.com
The Agrelo DF Jr. http://www.agrelo.com/dfjr.html