From Forum Nokia Wiki

Flash Professional 8 is the development tool of choice (currently) for Flash Lite applications. A free, 30-day trial is available for download.

Flash Professional 8 includes support for Flash Lite 1.1 applications out-of-the-box. The necessary Flash Lite authoring 2 update is available for free download from Adobe's Web site.

You can also download updates for the device profiles (phone simulators) from Adobe's Web site.

Adobe has already launched a new version of Flash development tool (part of the Adobe Creative Studio 3). In CS3 the mobile specific portion of the authoring environment has been detached to separate tool called Device Central CS3.