I've never found a very good solution for this. There are utilities out there that can convert SWF to various formats. I've found that there are often some issues in which they don't do a very good job, for instance in some cases flash will use hold frames instead of repeating frames where nothing on the screen changes....the conversion utilities treat this as a single frame resulting in a video that is really short.
The only dependable solution I found was to play the SWF and record the screen using Techsmith's Camtasia, which will allow you to export the video in any number of different formats (avi, quicktime, etc..)... though probably not an OMF.
Not the greatest solution...but it works.