I just installed FF3 and Flashtracer hasn’t been ported for this yet, so I had to look for an alternative. A friend pointed WinTail out (more detail later) and having that monitoring flashlog.txt:

• Windows: C:\Documents and Settings\username\Application Data\Macromedia\Flash Player\Logs\flashlog.txt or %AppData%\Macromedia\Flash Player\Logs\flashlog.txt
• OSX: /Users/username/Library/Preferences/Macromedia/Flash Player/Logs/flashlog.txt
• Linux: home/username/Macromedia/Flash_Player/Logs/flashlog.txt

Don’t forget to setup mm.cfg for traces to be actually logged.

WinTail: http://www.baremetalsoft.com/wintail/