It adds 4 new flags to any residence:
clanbuild - to allow clanners to build on your land
clanuse - to allow your clanmates to use stuff inside your house
clanmove - to admit only members of your clan to your party (falls back to move flag!)
clancontainer - to make a shared storage for your clan(?)
Source of this plugin is available on GitHub under zlib/libpng License.
You have to edit your Residence's config.yml (it's in your plugins\Residence folder). You have to add all these flags to Global (default: true), FlagPermission (default: true) and ResidenceDefault (default: false) sections. After that just restart your server and go add some flags. No commands, no config, just that simple.
Bukkit version 1.1R1 is minimum required, but this plugin works on most recent build also without any problems.
Thanks to authors of Residence, especially bekvon. Without his advise this plugin would never work as intended.