Great news for all Linux people and ones that would like to switch but can’t make it without good software support. Swaroop C H, The Dreamer Indian programmer, posted on his blog announcement of Flex Builder for Linux, and it’s officially supported by Adobe so it seems it will definitly make it’s way to the final realease.
Currently Flex Builder for Linux is in alpha but it’s working good judging by comments …

Flex Builder Linux works great in my Ubuntu OS.
For me there was no bugs yet,
compiling AS3, MXML with the SDK2 or SDK3 works fine!