Geheimnis supports GnuPG 0.9x
Geheimnis since 0.50 supports GnuPG 0.9x, and in future releases, will support advanced options like choosing the hash, encryption method, etc...
Use GnuPG in your own programms
Privacy Guard Glue (http://www.nessie.de/mroth/pgg/) is a library written in C to
add GnuPG support to applications. It uses the coprocessing interface of GnuPG.
An open, cross-platform journaling program.
A scientific plotting package.