AqBanking (library for online banking)

AqBanking offers an interface to generic online banking tasks,
bank information for the US, Germany, Austria and Switzerland
and country- and currency-related information.

AqBanking can be used by AqFinance, OrgaMon, GnuCash and KMyMoney
It supports HBCI (2.01, 2.10, 2.20, FinTS 3.00), EBICS (2.3 and 2.4)
and OFX Direct Connect.

Note: To have gnucash (as of 2013-12-28) use AqBanking, 
recompile gnucash with --enable-aqbanking.