How do I migrate my photo library from Lightroom 1.0 into Aperture 2?

How do I migrate my photo library from Lightroom 1.0 into Aperture 2?

I've got thousands of photos in an existing Lightroom 1.0 library and I want to move them to Aperture 2. Is there a way to do this while preserving the keyword tags and existing adjustments? Using a third party software to accomplish this is also an opton.