Flex SDK coding conventions and best practices:
Flex Coding Standards

ActionScript Bug reporting system:
Issue Navigator

Adobe Flex 3 Help Doc:
Help, Search API’s

Component Explorers:

• Flex 2 Component Explorer
• Flex 3 Component Explorer
• Flex 2 Charting Components Explorer
• Flex 3 Charting Components Explorer
• Ely Greenfield’s Charting Sampler (blog)

Style Explorers:

• Flex 2 Style Explorer (using this in Fireworks)
• Flex 3 Style Explorer
• Flex Builder 3 CSS Explorer
• Getting Started With Flex 3
• Theme portals: ScaleNine, FillColors, Fleksray
• Adobe Kuler (CMX articles part 1 part 2)
• Drawing API

Effects Explorers:

• Flex 2 Filter Explorer
• Flex 2 Primitive Explorer
• Distortion Effects Explorer
• James Ward’s Easing Function Fun (blog)
• Custom Easing Function Explorer (blog english)
• Ben Stucki’s Audio Visualization Explorer (blog)

Benchmark Explorers

• James Ward’s Census Benchmark Explorer (blog)
• James Ward’s BlazeBench (blog)

Application Explorers

• Adobe Developer Center Flex 3 Sample Applications
• Adobe Labs Flex 3 Network Monitor (docs)