The term virtual law currently has two main meanings: (1) part of real-life law as applied to virtual worlds (in narrow sense), or (2) law emerging through cooperation of virtual worlds' users/avatars in a virtual social reality.
Let's elaborate on this a bit further.
In each case the reference is given to a virtual world (in narrow sense) concept. Narrow meaning of "virtual worlds" words implies computer-based simulated environment through which users can interact with one another and use objects.
1. Virtual law as real law
Virtual law (1)
A typical virtual world implies a lot of legal issues, even before we get to the most fascinating ones (e.g. virtual property as an analogy to real-life property). There is a lot to be done to arrange a business, fix the terms with the relevant parties, run a payment system and so on in order to launch a virtual world. To be on a safe side, all of this requires legal input.
When a virtual world is launched, a lot of other issues may arise: online and in-game harassment and libel, virtual black market, enforcement of EULAs etc. This, again, has strong and, so to say, classic real-life law flavour blended a bit with the technical specifics of virtual worlds background.
All of the above implies that virtual law (1) is a real-life law as applied to virtual worlds (in narrow sense) determined by technical specifics of a virtual law.
2. Virtual law as, ahem, virtual law
Virtual law (2)
Let us imagine that a dwarf crafts a cudgel and sells it to some human passing nearby. It is clear that the dwarf has a property title in the cudgel by the right of property. The dwarf (let us assume that it is a female dwarf) may dispose of her property as she wishes. The passing-by human gives promise to pay, the dwarf provides consideration - the cudgel in question - and the contract is made.
Looks like an allegory for a theory of law class, doesn't it?
It is this discourse, where guilds or clans viewed as political structures seem appropriate.
Thus, virtual law (2) is a kind of law which is developed through virtual social communication in a virtual social reality of a virtual social world.
Both virtual law (1) and virtual law (2) should be differentiated from other related phenomena such as internet law, IP law and e-currency law although all of these are related phenomena. Virtual law practice/firms is a completely different issue as what is implied is just legal services rendered without any "physical" office.
Does virtual law (2) appeal to you?