From K2CC Wiki

APRS or the Automatic Position Reporting System is a packet radio system used to transmit position reports, weather reports, messages, and telemetry between amateur radio users.

APRS is most common on the 2M VHF amateur band, however HF and UHF bands are sometimes used. In North America, the APRS frequency is 144.390 MHz.

APRS Internet Tracking Links

Google Maps APRS
ON4SAX's APRS Tracker
K6IB APRS Tracker