Do you mean SWF (Shockwave Flash = the animation, the play button and other gubbins) or FLV (Flash Video = the actual video, which you are often able to sneakily download using UnPlug, KeepVid or Videodownloader)?
I doubt if VLC will support SWF in the forseeable future, there are no good open source decoders for this. Even reading the SWF to find where the FLV data is held would be, in my view, incredibly difficult due to it often being spawned from complex ActionScripts.
FLV support is already avaliable in 0.8.6. You can try the nightly builds (
http://nightlies.videolan.org/ ) - but be warned they are only development versions.