This script is a handy utility that generates bitmap font sheets from TrueType fonts. The script makes use of imagemagick, so you need to have imagemagick installed in order to use it.
Given the following command("/Library/Fonts/Comic\ Sans\ MS.ttf" is where the font Comic Sans can be located on my system):
python font_sheet.py /Library/Fonts/Comic\ Sans\ MS.ttf out.png
the script produces a font sheet named out.png:
As can be seen, the sheet has been properly padded so that its sizes are powers of two, so that it can efficiently be used in for example games(in this case, a 1024x1024 texture is created). Also, the characters are ordered after ASCII.