I did that yesterday.
Download the sonar demo from the cakewalk site, if you have VMware Fusion or Paralells, install it in that virtual machine. You can use Boot camp too.
Now, in windows, Launch sonar, click file, open, and select the CWB.
In the unpack bundle window click ok.
If your friend used a plugin that is not on the machine you'll get a Missing plug-ins window, just cick ok too.
Once the project is open you can play the song if you want.
Now you can click File, Export, OMF.
In the next window, choose a location for the omf file and click Save.
Don't change any settings in the save window, unless you want something special like split stereo tracks to dual mono. When it finishes, copy the omf file to your mac.
Now, in logic pro, start a new project with a single audio channel, and then click on File, import, and select the omf. Logic will ask you for a folder to unpack the omf to, make one and select it, if you don't, and you have the omf in your desktop, it will unpack all the files there, you don't want that for a 20 channel project, make a folder to unpack it.
Once the projext has loaded in Logic, save it.
Now you can work on it.
This way there's no need to convert files.
I hope this helps.
One note, check the tempo used in the sonar project, and use the same tempo in logic.
