What's a platform worth without an ecosystem? Microsoft is working very closely with industry partners to port HPC solutions over to also support the Windows HPC platform. Recently four major players announced their support for Windows Compute Cluster Server 2003:
Altair Engineering Inc., ANSYS Inc., CD-adapco and Livermore Software Technology Corp. ported their engineering software to Windows Compute Cluster Server 2003. The announcement was made at the Society of Petroleum Engineers Annual Technical Conference and Exhibition.
Supercomputing Online has details about the announcement and the partner solutions.