Finance::Quote is a Perl module which can fetch on-line stock quotes, including those from American, European, Canadian and Australian markets. Information from a number of investment houses is also available. Features include currency lookups and conversions, automatic failover support, and loadable user modules.
GnuCash allows you to track bank accounts, stocks, income, and expenses. As quick and intuitive to use as a checkbook register, it is based on professional accounting principles to ensure balanced books and accurate reports. It is backed by an active development community and is blossoming into a full-fledged accounting system.