Usually you should not copy the map file to the web2c directory. web2c is for use of configure files, for example updmap-local.cfg.
Usually map files go to fonts/map or fonts/map/dvips.
Your original problem seems to be that you didn't run mktexlsr before updating the updmap database. This caused the updmap cannot find the required map file. I don't know if texhash has any effect today though it is suggested in the PCTeX's website.
Anyway, you solved the problem yourself, and I think it is because as long as updmap can find the the map file, either in fonts/map, where it should be, or in web2c, it is ok. But it is still better to keep files where they are supposed to be. See the documentation for TDS.
Just a tip may be useful. I create a file updmap-local.cfg in /usr/local/texlive/texmf-local/web2c which contains the name of the map files in /usr/local/texlive/texmf-local/fonts/map. Since I got quite a few fonts installed in texmf-local, it is more convenient to keep a record of all map files. If say, I reinstalled the MacTeX, and the /usr/local/texlive/2010 folder is completely overwritten. All I need to do is
sudo mktexlsr
sudo tlmgr generate updmap
sudo updmap-sys
As long as my texmf-local folder does not change. Thus I don't have to type udpmap-sys --enable ... where ... can get quite long and error prone.
The name of the package for the purposes of tlmgr is not tabu.sty it's tabu because packages often contain a bunch of other files (documentation for sure, plus other files that you may not be aware of.) So the way to install tabu is:
sudo tlmgr install tabu
Best Answer
The answer is Will Robertson's comment:
You should be able to access it from Spotlight or Launchpad.
I recently installed BasicTeX myself, and I'm fairly sure
amsmathandmathtoolswere already included. I don't ever remember installing them myself, but my TeX Live Utility is listing them as "installed."tikzis not pre-installed.