For international flights, Windhoek is served by South African Airways, Lufthansa, Air Namibia and Air Berlin. Note that when booking a flight from the UK, it may work out cheaper to use easyjet or a similar budget airline to get to Frankfurt, and then book the long-haul flight to Windhoek seperately. For an initial look at flight routes and prices go to:
http://www.skyscanner.net

For car hire, the following is a list of pretty much all car hire companies in Namibia:
http://www.namibiafortheworld.com/car.html

Other useful, more general links are as follows:
http://www.natron.net/etour.htm
http://www.namibiatourism.com.na
http://www.namibian.org
http://www.bradt-travelguides.com/details.asp?prodid=69
http://www.namibia-facts.de
http://www.etoshanationalpark.co.za/index.html
http://www.nwr.com.na/activities.html

Read this incredible story of a ship wreck on the northern skeleton coast and the efforts undertaken to rescue survivors:
http://en.wikipedia.org/wiki/MV_Dunedin_Star

For a good selection of photographs illustrating the places mentioned on this site, see:
http://www.celnav.de/vacation/namibia2008.htm/