Probe is an addon that creates remote sensing devices called probes for all races. The devices are launched like torpedoes but have a range of several hundred light years. They travel at high warp speed to their destination where they commence transmitting data back to their mothership. The type and quantity of data send back depend on the class of probe.
In the Beta release there are only 4 basic types of probe:
To launch a probe your ship must have torp launchers of high enough tech level, and enough cash to pay for the probe. Set your ship waypoint to the probe's destination and the ship friendly code to 'c2p'... to launch a class 2 probe (the targetting beacon).
The probe information is included in a file called PROBEn.DAT that the host should sent to you. You need a copy of PROBE.EXE to be executed from your WinPlan UNPROC2.BAT script. More complete instructions come with the PROBE.EXE in the ZIP file.
Additional doc is included in the PROBE distribution zip file.