The Hardy repos have pspp 0.4.x in them, but 0.6.0 is out and it's really really incredible. If you have experience using SPSS, you will feel very much at home. It's not done yet (0.6 < 1.0) but it is much more capable and useful than the version in the hardy repos. The GUI (psppire) does have some limitations, but it's much better than any R-CRAN front-end I've ever seen. In time this program will become _the_ tool to point new Linux users to when they need a statistics tool that comes with a GUI.
As an added bonus some of you will be pleased to learn that the FSF have worked very hard to reproduce the delightful fortranesque world that is SPSS syntax. If you have to work with SPSS syntax or .sav files, this program is worth checking out. If you are already a wizard with R-CRAN, and don't need to share files / code with SPSS users, you are better off ignoring this post. Because of the brilliant structure R adopted for letting people write custom code/modules, R-CRAN has more functions and features than either PSPP or SPSS base. But, PSPP has a lot to offer people who need compatibility with SPSS or want a GUI. I'm sure that PSPP will (slowly) close the gap with R in the future.
The installation directions directions are pretty good but I had to install the ruby packages for most of the dependencies in order to get it to compile. So, if you just go through the dependencies and make sure you have the -dev and -ruby stuff, it works as advertised.
Conversely, I could send you the .deb file that I have but I feel obligated to tell you that it was created via checkinstall and it does not do dependency checking for you. I just wrote it to make it easier to remove / upgrade with Intrepid comes out. If you want it, PM me, and I'll send it to you.
For all you emacs fans out there (I am slowly becoming one myself) the program comes with a very useful mode called pspp-mode that will make a very nice addition to your collection of modes. If someone who actually knows LISP could look at this and tell me how hard it would be to fold this mode into ESS, I would love to learn more about that.