This was an interesting find this week - dssi-vst

Built using the DSSI API, dssi-vst is a wrapper that makes it possible for you to take your VST and VSTi effects and instrument plugins compiled for Windows, and load them into native LADSPA or DSSI plugin hosts.

Plugins run at full speed for most audio processing, although their user interfaces are slower because of the Windows emulation (you need to have WINE installed).

The system isn't perfect yet, and you won't be able to get all your plugins working, but it's a good start and future updates promise to bring even more functionality.

All in all, if you're using apps like Rosegarden, then this is a great piece of open source software for you written by Chris Cannam.

For more information go to: http://www.breakfastquay.com/dssi-vst/