Where instruction and technology meet for teachers and the classroom    
Life long learning is essential for success in everything we do including PowerPoint. These blogs will keep you up to date with the latest techniques and information that will continue to move your PPT's to new levels. * indicates the ones I never miss.
Maniactive; More Than PowerPoint Microsoft Powerpoint Team Blog
The PowerPoint Blog The Art of PowerPoint-ing
Presentation Zen * Luc's PowerPoint Blog
Excellence in Presentations David Paradi's PowerPoint Blog
Indezine, A PowerPoint Blog Beyond Bullet Points Blog
Relational PowerPoint Blog Tony's PowerPoint Weblog
Casey Hibbards Storytelling in PowerPoint The PowerPoint Ninja *
Speaking PPT * Presentation-Process *