Cautionary note on this:
While TypeTool has a number of useful editing features, it does not have the Transformation/Effects (and other advanced features) that come with its big brother FontLab 4.5. Thus it can not really be fully used in configuring digital type for letterpress. Also, and unfortunately, with this release, FontLab 4.5's upgrade price has been kicked up a bit in price, from $199 to $299 (for those who have a previous version of either FontLab or Fontographer). So its still either of these two, FOG or FL. Fontographer, however, like TypeTool, cannot be used to edit OpenType fonts.