Around a year ago, I remember reading the article The Era Of Symbol Fonts on A List Apart.
Despite it being a bit too evangelical and hyperbolic – as the elevation of “Symbol Fonts” into an “Era” in the title suggests, I suppose – the article had useful info.
More practical – and with an eagle eye on the downsides – here’s an article that goes into, in depth, the use of Icon Fonts as UI elements in web pages.
It’s a minefield still. Beware.
Bulletproof Accessible Icon Fonts