Cloudozer LLP is a company behind Erlang on Xen and related technologies. The technologies possess unique properties that allow creation of super-scalable zero-footprint cloud. More information about Erlang on Xen can be found on the community website - erlangonxen.org.
Erlang on Xen is open source under non-GPL license. Other licensing options are available from Cloudozer LLP.
A few places to start: