Thx zwetan from the FCNG mailing list one more time who found those interesting articles. Check them out
High Performance Web Sites: Rule 1 – Make Fewer HTTP Requests
High Performance Web Sites: Rule 2 – Use a Content Delivery Network
High Performance Web Sites: Rule 3 – Add an Expires Header
High Performance Web Sites: Rule 4 – GZip Components
High Performance Web Sites: Rule 5 – Put Stylesheets at the Top
High Performance Web Sites: Rule 6 – Move Scripts to the Bottom
High Performance Web Sites: Rule 7 – Avoid CSS Expressions
High Performance Web Sites: Rule 8 – Make JavaScript and CSS External