BLogs about Presentation Skills 2

http://www.123ppt.com/

http://www.presentation-pointers.com/

for money
http://www.inzones.com/powerpoint/
http://www.templatecentral.com/
http://www.crystalgraphics.com/
http://www.movieclip.biz/ movies for PowerPoint

free (?)
http://www.backgroundart.com/
http://free-ppt.com/ - a lot of advices