What version of iWork can I use with Snow Leopard Ver 10.6.8?
It should run in your machine, as it is stated under Apple's iWork: System Requirements that iWork '09 requires an Intel processor ( not a Core2Duo ) and Mac OS X v10.5.6 or later.

Here's all of the requirements:


  
  A Mac with an Intel, PowerPC G5, or PowerPC G4 (500MHz or faster)    processor 
  512MB of RAM; 1GB recommended 
  Approximately 1.2GB of available disk space 
  32MB of video memory 
  Mac OS X v10.4.11 or Mac OS X v10.5.6 or later 
  QuickTime 7.5.5 or later 
  DVD drive required to install 
  Some features may require Internet access; additional fees and terms    apply