Ug. Web development. Yes, we’ve come a long way, and we now have tools like Firebug (especially giving props to the embedded version) and De MonsterDebugger (DM).
But DM requires you to include a SWC in your SWF (at least for the cool features), which you can’t do if you’re trying to see the trace output of someone else’s file (and I’m talking about when you should be doing this – when it’s appropriate).
Also, DM suffers from a major problem that most trace log viewers do: they don’t escape strings. The problem then, is that the display attempts to render HTML content rather than show you the code. Ack.
So I whipped up a super-simple Flash Trace Log Viewer that escapes strings, and has a few more features. FInd it at SourceForge (or binary).
Oh, and if you don’t know about the Flash Debug Player (I found out woefully late in my Flash development career), download it here (search on that page for the “content debugger” specific to your system – i.e. Intel Mac), and get instructions on how to set it up here. “What is it?” you ask. It writes trace() results out to a text file, for old-school debugging.
By the way, I don’t have an official certificate, so this is personally signed. But you now have the source, so you can build your own, after verifying the code doesn’t do anything creepy. : D
And you’ll, of course, need the AIR runtime.
Here's how I did it... 
awesome tool — thanks Thomas!