Andel 3w's
Covers everything from ticket prices to traffic cops in the Czech capital.
http://www.prague.dk/prague/english/pragtr01.htm#tr1

B2C Worldwide Hotels
General information about the transport options available to travellers to Prague.
http://www.b2c-prague-hotels.com/transport.shtml

BUG
Offers a basic overview of the transportation options in Prague.
http://www.bugeurope.com/prague/ga.html

DP-Praha
Click on the "Search for Links" section on this page to access an interactive Prague public transport route planner.
http://www.dp-praha.cz/en/index.htm

DP-Praha
Official source of information about the city's metro, trains, trams and buses.
http://www.dp-praha.cz/en/index.htm

MyCzechRepublic
Prague's transportation network explained.
http://www.myczechrepublic.com/prague/transportation.html