Since PPT 2000 you have been able to embed TrueType fonts, although I am not
certain of how all appear on a Mac. Embedding does increase the file size,
make saves alot slower and it needs to be a non-licensed font (when saving
the presentation you will receive a warning if it is a licensed font).
To embed go to TOOLS >> OPTIONS >> SAVE >> check the embed dialogs at the
bottom.
For Macs, no. Mac OS doesn't support font embedding, or at least doesn't
support the type of embedding that Office apps use.
One possible workaround is to distribute a PDF instead of a PPT/PPS file. Font
embedding in PDFs is cross-platform compatible. PDF also offers a more useful
security model.