The American Typewriter comes by default on Mac machines, but not on Windows. If those in my agency who need to use this font on their PC, do they have to purchase a license for it, or could I just give them the font to use?
In terms of technology, likely no problem. Font file formats are mostly cross platform these days (OSX and Windows 7 can handle most font file formats). Legally, though, it's murky. The fonts that come with OSX are licensed with the purchase of the Operating system. Technically, you are allowed to use them with the operating system...but not on other machines.