Preprocess

Sass

• http://www.phpsass.com/
• http://code.google.com/p/phamlp/ - older

Other

• csscrush - An extensible PHP based CSS preprocessor

• PCSS - Shortcut-oriented Server-side CSS3 Preprocessor
  • Pre-defined CSS constants and PCSS functions to make the CSS writing more intuitive and to make the code slimmer and even more readable
  • Class nesting
  • Variables that can hold any kind of data
  • Default unit and default image directory to set for pre-defined functions
  • @font-face shortcut with server-side browser detection for slimmer resulting code
  • Browser-specific shortcuts are detected on server-side to avoid redundant commands (like many "-webkit", "-moz", etc.)
  • Minifies the resulting CSS file
  • PHP5