If you search for 'Picalo' these days and tell Google that yes, you did mean to spell it that way, you still get some results related to audit and fraud data analysis but might struggle to find a working copy of the package.
Rewinding about ten years it was released by Conan Albrecht as a scripting-oriented free alternative to the main two audit data analysis packages, ACL and IDEA – tools that let people filter, join and do other database type things in a structured and reproducible way. Development ceased in 2010 with the author turning his attention to educational textbooks.
You can currently still browse around http://web.archive.org/web/*/http://picalo.org/ for an overview, for example http://web.archive.org/web/20120116043518/http://www.picalo.org/
For coders, https://pypi.python.org/pypi/picalo has the Python libraries without the GUI and docs can be found at https://web.archive.org/web/20110915213253/http://www.picalo.org:80/download/AdvancedManual.pdf or if you prefer a GUI some links here work and the ones you probably want are current-picalo.installer.exe or current-picalo.tar.gz for Windows or Linux: http://web.archive.org/web/20140205060118/http://www.picalo.org/download/
As far as then getting it running goes, the Windows installer still works, but without a maintainer the Linux version has been left behind by its dependencies. And whilst in theory Python can handle multiple versions being on a system – https://wiki.wxpython.org/MultiVersionInstalls – doing so eluded me despite tips from others;
According to that the last Picalo release is supposed to be okay with Python 2.7 but needs wxPython 2.8 rather than 3.0 – and I didn’t have any luck attempting a parallel install, so (again following a pointer in that thread) I got the source package running by installing Xubuntu 14.04 in VirtualBox and then wxpython 2.8 – which isn't a terrible solution in order to run a specific piece of software, but if anyone does have a reproducible method of getting it work on current Ubuntu variants that’d be appreciated.
Whilst I didn't mean this post to be a review, anyone with some familiarity with IDEA and ACL will undoubtedly come to the conclusion that Picalo is a far less polished product. In general if you were looking to build a CAATs workflow I’d suggest folk learn to use Excel for simple stuff, SQL for more complex things, and build an application with IIS or LAMP stack software for anything beyond that; they’re widely available and involve fewer support issues than trying to get an old GUI working, although the libraries themselves may be worth considering for programmatic manipulation.
Like in other fields, though, it’s generally more important that budding data analysts get to grips with standard techniques and concepts than specific software, and if you can filter, group, join, etc and use regular expressions that’s more than half the battle. See this blog entry for Excel tips.
If you do get Picalo working and find it useful you might also appreciate basic training materials: http://www.iacae.org/English/Training/CAATs_Courses_Free_Picalo.php