I've made a system that makes it easy to set up claimable portals to player plots on a multiplayer server. Ops can use a command book to easily set up portals - each portal has:

• A teleport block that teleport to certain coordinates.
  
• A control block used to claim the plot and control who is allowed to enter.
  
• An indicator block showing whether or not it is claimed.
  
• A sign showing who owns the plot.
  

Players can visit any unclaimed plots to scout out a location they want, then claim a plot by simply stepping on a block and clicking a chat link. Once claimed, the portal block will only let the owner in.

To allow visitors, the owner can step on the control block once someone else is on the portal block. The owner then gets an option to allow that person to enter as another clickable chat link.

To install the system, either use MCEdit to add the schematic, or download the four commands needed to spawn the structure. Please see the video for detailed instructions on how to do this correctly.

Commands: One Two Three Four.