One of my favourite tools / applications / websites is http://icomoon.io/. I spent a long time looking into icon fonts with the advent of retina displays and it became fairly obvious that there was only one real way currently available for shier ease of use and that was ICOMOON.
How to use: create icon in illustrator > save as SVG > import to ICOMOON > save as font > use.
If you are not using bespoke icons they have a huge library that you can chose from.
This is why when building this site I decided to use ICOMOON logo to define icon fonts as a skill 🙂