7 Free Tools to Minify your Scripts and CSS

1. JSMin (JavaScript Minifier) - removes comments and unnecessary whitespace from JavaScript files
2. JSO (JavaScript Optimizer) - allows you to manage your JavaScript and CSS resources and to reduce the amount of data transfered between the server and the client.
3. Packer – An online JavaScript Compressor
4. JSCompress.com – Online tool that uses either JSMin or Packer to compress your files
5. CSS Compressor – Online tool that compresses your CSS file
6. DigitalOverload JavaScript Minifier – Online tool that minifies your JavaScript files
7. YUI Compressor – A JavaScript minifier designed to be 100% safe and yields a higher compression ratio than most other tools.

http://www.devcurry.com/2009/11/7-free-tools-to-minify-your-scripts-and.html