The steps to make a Raspberry Pi supercomputer can be downloaded here [9th Jan 2013 update]: Raspberry Pi Supercomputer (PDF).
You can also follow the steps yourself here [9th Jan 2013 update]: Raspberry Pi Supercomputer (html).
The press release (11th Sept 2012) for our Raspberry Pi Supercomputer with Lego is here: Press Release University Page
The press release is also here (PDF): Press Release (PDF).
Pictures are here - including Raspberry Pi and Lego: Press Release (More Pictures).
We wrote up our work as a scientific journal publication where you can find further technical details on the build, motivation for the project and benchmarking.
The reference to the paper is:
Simon J. Cox, James T. Cox, Richard P. Boardman, Steven J. Johnston, Mark Scott,
Neil S. O'Brien
Iridis-pi: a low-cost, compact demonstration cluster
Cluster Computing
June 2013
DOI: 10.1007/s10586-013-0282-7
These are some links you may find helpfulul