Adobe's DNG converter is easy to use. I have used it for raw files of my Lumix.
It is free, so you could download it and give it a try.
The dng's from DNG converter are supposed to be supported by Aperture:
Aperture works with most DNG files generated from cameras that support this format and with DNG files generated by the Adobe DNG Converter with the “Convert to Linear Image” option turned off.
Only I am no longer quite convinced. I used to be able to import dngs created by Adobe's DNG converter, but since the upgrade to MacOS X 10.8.4 does Aperture no longer accept newly created dngs.
But any software that will convert the raw to tiff will do - the software that comes with the camera or Photoshop, for example.