Slides

http://www.slideshare.net/search/slideshow?searchfrom=header&q=Group+Discussion

GD tests you in the following

Body language

http://knowbodylanguage.blogspot.com/

Communication skills

http://communicationinformation.blogspot.com/

Self confidence

http://learnconfidence.blogspot.com/

Team skills

http://teampath.blogspot.com/

Listening ability

http://listeninfo.blogspot.com/

Ability to present your views logically

http://knowpresentation.blogspot.com/

Time management

http://handlingtime.blogspot.com/