To design a font on linux you can use fontforge. http://fontforge.sourceforge.net/
As part of my learning graphical design, I have become interested in finding out how fonts work and how to design fonts. I think learning to design a font will give me insight into other fonts. Much like how learning assembly language gave me insight into how computers work.
Creating a font on linux with fontforge is the way to go I think. I haven't found any other way to create a font on linux yet! It was quite hard to find fontforge for designing fonts on linux too.
It's a time consuming thing - designing a font. That I think will take years to figure out. I don't expect to make a great font, however I think there is room for creativity in fonts yet. So I hope to make something useful and learn something on the way.
I guess I have made bitmap fonts before including the animated one on f0o.com http://f0o.com/. However crude it might be ;)
True Type Fonts .(ttf) fonts contain a virtual machine, much like postscript. With it you can instruct how each character is rasterized. So to make fonts well you need to be able to program this virtual machine. So like many other areas of graphics - a knowledge of programming can help you to design a good font. There are some tools for working with ttf 'hinting' instructions here(including a compiler from a C like language): http://home.kabelfoon.nl/~slam/fonts/