See here. These are in testing, so please report any bugs/errors. mpiBLAST is of course is one of the original cluster-accelerated BLAST implementations, being developed by Wu Feng’s group at VT.
IMO there is a strong need for applications like this, as well as mpihmmer and others. As data set sizes continue to grow at exponential paces, we need tools that can scale to the need. mpiBLAST is definitely in this set of tools … being an enabling technology to perform analyses at scale, that might not be possible without it.