The depletion of remaining IPv4 space is not a “sexy” topic, but it’s a very important one.
RIPE, which is charged with the IP space for Europe, has implemented a policy change regarding the reallocation of IP space.
While this may sound very technical, what it means is that they’re streamlining the process for freeing up and reusing IPs. Of course, in reality, the only longterm solution is to push IPv6 adoption.
You can read the policy proposal on their site as well as the modified final policy.
About 6 months ago the Internet Governance Project published a very interesting paper on IP Transfer Markets, you find it at http://blog.internetgovernance.org/blog/_archives/2008/7/13/3791187.html
Francesco
I think Jay Daley posted about it on the Nominet blog as well
Michele