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

High Performance Web Sites: Rule 9 - Reduce DNS Lookups

Ok, a thread you should read every day as senocular is updating it every day.
You could find lots of tips for AS3. More than tips, it’s stuff you need to know. SO just run HERE

Some useull links for those who still didn’t look at AS3.

>> Flash Profesionnal 9 Preview - This is flash 8 with AS3 support

>> PDF Documentation - Complete doc for as3

>> Know Bug in AS3 - A list you should check sometimes, as it’s updated. Check the bug before starting a development with AS3

>> AS2 to AS3 migration - All you need to know if you are a AS2 developer

>> Start developing with AS3 - A basic introduction of AS3 development

>> Programming with AS3 - Another tutorial

>> Live Doc - the LiveDoc for AS3

>> Examples - Some Examples for AS3 development

>> Labs - Adobe Labs about AS3

>> Packages - Free AS3 Library

>> Warning Message - Listing of warning messsage you could encounter

>> E4X Specification - Specification of the norme used by AS3