Here is a link to a technical report from the National Imagery and Mapping Agency that talks all about WGS84. (World Geodetic System of 1984):
I hope to read trough this report on one of my upcoming vacations, since WGS84 is such an important part of what I do as a surveyor and GISer.
The report looks like it can be understood by most people, without a need for an advanced degree in mathematics or rocket science. :]
I hope others will find it useful.
The Sunburned Surveyor