Americans in Prague
Some pointers on English language church services in Prague.
http://www.americansinprague.com/living/religious.html

Prague City Server
Information on the various different religious services held in the city.
http://www.a-zprague.cz/prague_guide.php?lang=en&parent=verici

Prague Information Service
Index of foreign language church services held in the city. The page also includes a section on synagogues.
http://www.pis.cz/a/culture/0308/0aboh.html

Prague.tv
A guide to churches, mosques and synagogues in Prague.
http://www.prague.tv/venues/list.php?cat=churches