GnuCash:About
From GnuCash
GnuCash is a free software accounting program that implements a double-entry bookkeeping system. It was initially aimed at developing capabilities similar to Intuit, Inc.'s Quicken application, but also has features for small business accounting.
GnuCash is known to run on Gnu/Linux, OpenBSD, FreeBSD, Solaris, OS X, and other Unix-like platforms. A Microsoft Windows (XP or newer) port was made available starting with the 2.2.0 series.