http://www.sothink.com/flashdecompiler/

From SWF to fully editable FLA in seconds. This is a powerful tool.
Sothink’s latest installment in the SWF Decompiler series is just that. Keeping pace with the latest features of Flash, it offers developers the means to re-create (not completely faithfully, but nigh on) their work back into FLA format.
The big new feature in this version is the Actionscript 2.0 support. AS2 classes are exported and written into .as files, preserving their package structure and a complete Flash Project file is created containing all the exported files.
In addition to that, embedded assets can be exported to their native formats; sounds can be saved as MP3 or WAV (using the packaged LAME MP3 encoder), videos as FLV, images as BMP or JPG and actionscripts from selected frames can be saved individually to text files.

When recreating the FLA, SWF Decompiler actually does a really good job of rebuilding. Labels, scripts and frames are replaced true to the original and the end result is that you have a good, solid representation of your lost work that, with minor amendments, you can continue to develop.
The flip side is that your code will be different. Variable names are renamed (maintaining functionality, but not readability) and labels are often on different layers, albeit in the correct place in the timeline. Any formatting in your library won’t survive and library items’ names are reduced to “Symbol 1″,”Symbol 2”, etc..

Other features of this package include the Sothink SWF Catcher. Installing this alongside SWF Decompiler will give an extra right-click option whilst browsing web pages that, when selected, displays details of all the flash content in the current browser window and options to save the item(s) to your computer or send them straight to the decompiler to have a good poke around.

To be fair, if you deleted your source file, then you need source control, tape backups or just a little more care and this product will save you an awful lot of re-development, headaches and possibly your job! For under $80USD that’s a pretty good deal.

Price: $79.99
Buy it now