Squad Lists

Here are links to each country's World Cup squad on Wikipedia. The Fifa site is of course the definitive, official site, but it's pretty light on info (just Player Name, Squad number, and Official Position).
Wikipedia gives the same info, plus the player's age, club, and number of caps (appearances for the national team).
It's also updated pretty quickly: Marco Reus's name was removed from the German squad the same day as his injury was officially announced.

Group	Country		Group	Country
A	Brazil		E	Ecuador
A	Cameroon		E	France
A	Croatia		E	Honduras
A	Mexico		E	Switzerland
B	Australia		F	Argentina
B	Netherlands		F	Bosnia & Herzegovina
B	Chile		F	Iran
B	Spain		F	Nigeria
C	Colombia		G	Germany
C	Greece		G	Ghana
C	Ivory Coast		G	Portugal
C	Japan		G	United States
D	Costa Rica		H	Algeria
D	England		H	Belgium
D	Italy		H	Russia
D	Uruguay		H	South Korea

The South Koreans win the prize for the best names, especially their reserve goalkeeper.