Just read an article in Linux Journal May 2004 about SQL-Ledger
(www.sql-ledger.com).  The writer actually uses the program in the running of his consultancy 
business.
I bet that OpenGroupware will eventually have some of this functionality too, if it doesn't already.
I also found http://freshmeat.net/projects/egs/  EGS.

More programs are found here: http://freshmeat.net/search/?q=CRM&section=projects&Go.x=14&Go.y=9

Brian Kelsay

>>> Micke Ohrberg <micke@kc.rr.com> 06/11/04 08:09AM >>>
Hello all,

  Does anyone know of a good, open-source package that will help in
  running a business? I'm thinking of something along the lines of
  invoicing, CRM - you know, regular business stuff.

  And yes, to keep it somehwat on topic - it will be running on a
  Linux box :D  

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