|MadSci Network: Genetics|
While I could write you an explanation of the Human Genome Project and how sequencing is done, this has been done probably better than I can in a variety of places. Here, then, are some links to sites with a wealth of information on this topic:
The Human Genome Project
(note that under "General Information" there's a Frequently Asked Questions link that includes "How do you sequence a genome?")
This is a course site in Britain that gives lovely diagrams and nice explanations of Sanger (dideoxy) sequencing technology, the shotgun sequencing strategy, etc.
University Genomics Tutorial
This site gives a VERY detailed overview of the entire sequencing process.
Department of Energy genome sequencing facts
Another nice page with basic overview of the processes used.
Hope these are helpful.
Try the links in the MadSci Library for more information on Genetics.