If you try importing MPEG videos that have AC3 audio (especially from digital camcorders) into Premiere Pro CS3, then the audio will not be recognized and will not play back.  This DLL file will fix that problem.  Put this DLL into your Premiere directory (e.g. "C:\Program Files\Adobe\Adobe Premiere Pro CS3\").  This is the same file that can be found in Adobe Encore CS3 if you installed it.  I made this torrent so that you won't need Encore CS3.

Also, you may want to download the 3.1.1 update from Adobe (adobe.com/support/downloads/detail.jsp?ftpID=3817).  The update fixes red flashes which occur if using MPEG videos in your project.  If you get the 3.1.1 update, you will have to replace the premiere.dll again.  It seems to work fine using the cracked premiere.dll that was included with the .daa release.