Use of Open Source Software in Legal Firms?

jhenkins asks: "This is a question to all of the legal beagles out there, especially practicing lawyers and advocates. Normally there are quite a number of restrictions posed on law professionals with regards to file formats by courts etc, but I would like to know whether there are some success stories out there. It would be very interesting to get some opinions in this field, because where I come from (South Africa) this is an almost *total* M$ stronghold. The only area where I saw a really big score for Open Source is the adoption of things like Kolab for groupware and scheduling. So, do you use Open Source software in your line of work? If you do, please let me know what you use and for which purpose (things like document management, knowledge bases, word processing et al). Thanks!"