Metrowerks has split CodeWarrior for Macintosh and CodeWarrior for BeOS into two separate products. You can use either product, but to develop for the BeOS, you need the BeOS headers and libraries. As of CodeWarrior 11, these are no longer included in the CodeWarrior for Macintosh package.
The BeOS CD-ROM comes with a version of the Metrowerks BeIDE that has a linker limited to 64K, but you can upgrade to the full version through Metrowerks. The CD also includes all the headers and libraries necessary to develop for the BeOS. The headers and libraries are also on the Be web site:
You cannot use Symantec's compilers at this time, unfortunately.