I'm starting a .deb package for OpenCASCADE for users of Debian and Ubuntu. You can see the latest version at http://lyre.mit.edu/~powell/opencascade/
Version 6.2.0-2 which is currently uploading is usable (unlike 6.2.0-1), though not complete. (It also looks like an NMU because I'm an idiot and didn't transfer my .emacs into the unstable chroot where I built it...) I hope to upload the package into Debian unstable at some point soon, when I consider it "complete", e.g. with examples, one or two fixes to debian/rules, etc.
Incidentally, for some reason "make -C ros install" is not installing the header files. This is not a problem, I am copying them by hand in the debian/rules install target.
All issues in the package are documented in README.Debian.html