下載地址一：http://download.macromedia.com/pub/flex/flex_builder/FB3_win.exe
大小： 424 MB ；未進行壓縮的 Flex Builder 3 安裝文件
不用註冊登錄，可以直接下載。
下載地址二： http://trials.adobe.com/Applications/.../FB3_WWEJ.exe
大小： 385.84 MB ； 已經壓縮的 Flex Builder 3 安裝文件
需要註冊登錄，纔可下載。
Flex builder 3.0註冊碼（已經試過的，可用的）：
1377-4168-2018-0771-2432-1495
1377-4760-3354-0772-2773-8996
1377-4165-2080-7265-7813-8901
1377-4964-5021-8182-2399-8235
Flex builder 中要進行調試，就必須安裝含debug的flash player版本。
下載鏈接地址：
Adobe Flash Player 9 — Debugger Versions (aka debug players or content debuggers) for Flex and Flash Developers
12/3/2007 Updated debugger versions of Flash Player 9 (aka debug players or content debuggers) are available for Flex Builder 2 users and Flash CS3 Professional users. These new players are version 9.0.r115.
Download the Windows Flash Player 9 ActiveX control content debugger (for IE) (EXE, 1.59 MB)
Download the Windows Flash Player 9 Plugin content debugger (for Netscape-compatible browsers) (EXE, 1.56 MB)
Download the Windows Flash Player 9 Projector content debugger (EXE, 3.69 MB)
Download the Macintosh Flash Player 9 Plugin content debugger (Intel-based Macs) (DMG, 5.35 MB)
Download the Macintosh Flash Player 9 Plugin content debugger (PowerPC-based Macs) (DMG, 2.41 MB)
Download the Macintosh Flash Player 9 Projector content debugger (ZIP, 4.81 MB)
12/3/2007 Updated Linux debugger versions (aka debug players or content debuggers) of Flash Player 9 are now available. Additionally, the Linux standalone player (projector) is available for developers who wish to publish projectors on Linux operating systems.
Download the Linux debugger and standalone players (TAR.GZ, 9.29 MB)