There's a number of programs out there that are quite popular. Some of them are easier to use than others, but often not as advanced.FontStruct
is fairly popular, and is an online tool that requires Flash. It is very easy to use.FontForge
is likewise also popular. While it is powerful, it's also a bit cumbersome since it's designed for Unix and Linux systems. There is a Windows version available.FontCreator
is easy to use, but the more advanced features are hard to find and the full version is a paid program.
I'd probably recommend FontStruct if you're just looking for some basic prototype fonts. You can probably polish it up later using other programs.
Also, I'm not sure, but there may be some art programs out there that allow for plugins to edit and save fonts.
I hope this helps!