True to Smashing form, they have collated a bunch of useful information about the technical aspects of web typography, everything from glyphs to grids. Its a very useful reference. Note of caution however, there are some errors in the article in relation to type measurement on the web, mainly the part about em values. Em is a relative measurement on the web and is a handy work around W3C standards for designers who want to control type size but want to avoid fixed size settings in pixels.
Earlier this month Smashing also did another piece on web typography which focuses on the @font-face rule and the various aspects around embedding fonts on the web.
Another useful reference is Khoi Vinh’s book published just before Christmas on grid principles for web design.