Adobe Illustrator is a drawing and illustration program from Adobe, the same company that creates other products such as Photoshop, InDesign, Acrobat, etc. Illustrator, since the last few versions includes options to directly export graphics for Microsoft Office applications including PowerPoint.
Here are some Illustrator related pages on Indezine:
Artlandia SymmetryWorks 5
June 24, 2009
Artlandia LivePresets
July 28, 2008
Artlandia SymmetryWorks
January 31, 2007
Creating Spirographs with Adobe Illustrator
November 23, 2005
Creating Photoshop Shapes From Illustrator Drawings
November 26, 2004