Clustal Omega is the latest addition to the Clustal family. It offers a
significant increase in scalability over previous versions, allowing hundreds
of thousands of sequences to be aligned in only a few hours. It will also make
use of multiple processors, where present. In addition, the quality of
alignments is superior to previous versions, as measured by a range of popular
benchmarks.

WWW: http://www.clustal.org/omega/