Contrary to rumors posted on Unicode discussion boards, Klingon is NOT part of the Unicode specs. It is however part of the ConScript Unicode Registry maintained by John Cowan and Michael Everson.
The CSUR is a place where “artificial scripts” (including those created for fictional languages) can be quasi-encoded into the Private Use Area (PUA) blocks of Unicode. These were created for the exact purpose of allowing different user communities to formulate a standard to exchange data among themselves with characters not currently in Unicode. This registry allows a community to assign numbers in the PUA to a script then publicize it. The nice thing is that you could begin something like a Tolkein or Star Trek script containing all the scripts of the fictional universe.
Scripts included in the registry include Klingon, Ferengi from Star Trek, Tengwar and Cirth from the Tolkein Lord of the Rings trilogy, scripts from the Ultima game and even Seussian Latin Extensions…plus a whole lot more scripts that quite frankly, I have never heard of.
Anyone using the Private Use Area should note that these assignments are not officially recognized by Unicode and that many groups use the PUA for their own purposes. For instance, Microsoft fonts include special math symbols in the PUA (some of which have Unicode points outside the PUA). Academic consortia also use the PUA to include extra characters (e.g. extra phonetic symbols, extra medieval abbreviations and so forth) not in Unicode.
Still it’s a way to get some sort of standard enacted.