For those unsure of what a weather spotter/storm spotter does, they are like storm chasers but do not actively hunt down severe storms but rather report any severe weather which occurs in their location to the appropriate weather information centre. For South Africa this would be the South African Weather Service, the SAWS does urge residents to report back severe weather events such as damaging winds, hail, tornadoes, floods etc. Reporting these incidents plays a vital role in the collection of data for archived references as well as improving weather forecasting.

A sad truth is that there are very few people who report back on severe weather events and even less that are actual spotters. One of the reasons the United States warning systems work effectively is due to the fact that there are thousands of spotters who report back on severe weather events and thus allow the weather services to put out warnings in real time situations. 

Becoming a skilled spotter takes experience and some learning, though anyone is able to report events such as hail and damaging winds. Situations that precurse tornado development such as rotating wall clouds often require the spotter to know what he is looking at.

Below are some PDF files for those interesting in learning about spotting or even just learning more about storms.While they are issued for American citizens much of what you read will remain the same regardless of ones location. The biggest challenge may be that you will need to convert to the metric system in some cases.

NWS Basic Storm Spotter Field Guide

NWS Advanced Storm Spotter Field Guide

University of Illinois Storm Spotter Guide

Severe Weather Watcher Handbook

http://www.srh.noaa.gov/oun/stormspotting/basics.php