Our new C++ library is pretty much complete. We now have a simple, clear and uniform means of performing a host of activities in C++. We even added an easy-to-use CGI and Fast CGI framework that makes writing C++ CGI interfaces a snap. I've created a few already and, to date, it's been quicker to develop than using the Perl CGI module - it has support for forms, cookies, sessions and a templating engine.
A lot of the library's success is due to reuse of existing components, a few previously developed internally but most created by third parties. Notable support libs include the previously mentioned MySQL CPP API, and the absolutely incredible BOOST library.
I don't think I can overemphasize how useful boost has been to Psychogenic. To date, I've been using (in no particular order) the regular expression, the smart pointer, the generic graph, concept check and tuple components. And those are the ones I can remember off the top of my head! I am still enjoying periodically visiting the boost library list - if you're into C++ and don't know boost, I suggest you go have a look and read up on the first component that strikes your fancy; chances are it will eventually be useful.