My friend and I both have bukkit servers but his is not very popular. Do you think it would be possible to create a plugin that both of us could get that allows servers to be linked together when they are both running and you can put on a sign somthing like [linkip] underneath [ip address] on a nether portal and you would come out in the other servers nether portal that says the same thing but with your server address EDIT by Moderator: merged posts, please use the edit button instead of double posting.
There are already two plugins that do that... server port and bukkit link, search for it in the get plugins sections