As you know many radio amateurs collect wab squares, and you may have been asked for your wab square, but may not have known it or how to find out how to work it out. well here is a quick guide to help you out. Basically the wab square is the 10km os grid square, so you need the 1st and 4th number of the os grid reference and the two letter reference of the 100km square.
This is how you work it out:-
1) Go to www.streetmap.co.uk
2) Enter your postcode and then click the link saying "click here to convert co-ordinates" which is located below the map
3) A window with various co-ordinates will appear.(This is mine)
OS X (Eastings) 392547
OS Y (Northings) 282773
Nearest Post Code DY9 9DE
Lat (WGS84) N52:26:34 (52.442871)
Long (WGS84) W2:06:40 (-2.111074)
4) Look for the one named "LR"
5) In my case it says SO925827
6) The WAB is the first two letters plus the 1st and 4th number.
7) My WAB is SO98