Answer
ArcMap 9.x and above recognizes and uses TrueType fonts(*.ttf), PostScript Type 1 fonts (*.pfm), and OpenType fonts (*.ttf, *.otf).
ArcMap 8.x recognizes and uses TrueType fonts for all text and labels. For PostScript printing, and exporting to EPS and PDF files, ArcMap 8.x can either download TrueType fonts in the map to PostScript Type 3 or map the TrueType fonts in the map to a resident PostScript Type 1 on the system.