Latest stable version (0.91)
Inkscape is pre-packaged for most of the widely used free GNU/Linux distributions. So your package manager / app store should be able to find Inkscape in one line. Keep in mind that the version offered in your distro's repositories is not necessarily the latest version.
Red Hat: Coming soon via yum
OpenSUSE: Package Search
If you prefer, you can install Inkscape from source: Download sourcecode
The source code for the prior stable release 0.48.5 is available as well from this page.
Unstable Release Packages
- Package repository for Ubuntu