avarInstalling DraftSight on Ubuntu 64-bit
This has been tested in Ubuntu 10.04 LTS 64-bit, but there's no reason it shouldn't work in other versions. First install the ia32-libs 32-bit compatibility library (just click on the link and the magic of apturl will take care of the rest). Update: as some commenters posted, it turns out that forcing the installation of the 32-bit package prevents the automatic installation of some required dependencies, thus blocking the DraftSight install (as they were already installed on my system I didn't have this problem). To circumvent that, make sure that these three packages are installed as well before continuing: libaudio2, libdirectfb-extra and libxcb-render-util0. (To get these, I checked the DraftSight.deb package with GDebi in a brand-new Ubuntu 10.10 32-bit install.)
Then, open a terminal window (go to Applications > Accessories > Terminal) and type the following command:
sudo dpkg -i --force-architecture DraftSight.deb
Of course, for that to work you need to be in the same directory the DraftSight package is in. If you're not sure how to do that, just open the folder where the file is located, click on the file, drag & drop it on the terminal window. The full filepath will be added automatically. Hit enter, type your password.