I realize not many people on lainchan would be too interested in calligraphy. However, maybe someone else could benefit from this. :)
I look around and I found this software (My specifications were multiplatform and FOSS) http://fontforge.github.io/en-US/
There's another one, called GNU Font Editor, but it requires you to compile it and I figured not everyone would have the technical ability to compile this type of software. I will note it though, since I'm sure there are people would wouldn't mind it. (It's based on GIMP)
The other thing, I found these calligraphy pdf's that seemed like they could be a helpful introduction to it.
I'd recommend starting with either "The Art of Calligraphy" or "Modern Calligraphy and Hand Letting". Both are introduction books. "The Art of Calligraphy" appears to be a more broad scope than "Modern Calligraphy". The other two seem like intermediate books.
I uploaded them and included a md5 checksum. https://mega.nz/#F!UMsH2YIJ!IDkvxkT-5rslvdpMiOhVWw