The Hamburg Sign Language Notation System, HamNoSys , is a "phonetic" transcription system, which has been in widespread use since its original version - in the tradition of Stokoe-based systems - was published over 20 years ago.
The current version 4 takes into account practical experiences in the use of the system and also results of sign languages other than ASL, which invalidate several implicit presumptions in HamNoSys. By doing that, it exceeds the Stokoe system in terms of structure and expressive power, as well.
HamNoSys does not refer to national diversified finger spelling and therefore can be applied internationally.
The writing symbols are available as a unicode-based character set for various operating systems and can be downloaded for free.
The Hamburg Sign Language Notation System is also a basis for a series of avatar controls (cf. here). For learning HamNoSys the availability of avatar software is useful as you can verify own notation attempts at once.
(Hanke, T. (2004), “HamNoSys - representing sign language data in language resources and language processing contexts.” In: Streiter, Oliver, Vettori, Chiara (eds): LREC 2004, Workshop proceedings : Representation and processing of sign languages. Paris : ELRA, 2004, - pp. 1-6.)
Platfom independent input palette (browser based, no need to install font)