> I am looking for some elevation data to map in R for Cape Town, South Africa.
> Can it be found in any packages or R data bases?
R has a well developed set of packages for geospatial analysis as well as an active mailing list, R-SIG-GEO. I suggest that you first do a google-search with terms:
shape file elevation map cape town south africa
After you have put some search time into this, you will be in a better position to ask for help on the correct mailing list. I do not know if that mailing list is mirrored on Nabble. Generally it is recommended that you subscribe to R support mailing lists rather than use Nabble.