[M.D. Holloway]

lendaddy,
I use Excel and Minitab to do the number crunching. As far as software goes, here are a few ideas that my buddies at ASQ provided me a while back:

Six Sigma Software Suite, Quality America, Inc.

The Six Sigma Software Suite provides the tools you need to attain the six sigma level of process performance. This software suite contains four (4) modules including SPC-PC-IV, DOE, 7MP and Flowcharting/Cause & Effect. With the ability to share information between the four modules, you can perform multivariate regression analysis and plotting within the DOE module on SPC-PC-IV data files, convert flowcharting files to 7MP diagrams and do control charting on DOE data files. $800.00

and for a learning tool:

Total Quality Tools Software for Windows by PQ Systems:

This easy-to-use software version of the Total Quality Tools book (P697) contains detailed information on each of the 21 tools described in the book. It presents each tool in a systematic, six-step approach so that users know what to expect.

This software program teaches not only how to construct the tools, but also when to use them using clear and concise language. Included is a glossary of terms which allows users to clarify terminology or recall formulas throughout the use of the program. This system also includes a summarized pocket version of the book Total Quality Tools.
Tools Featured:
Affinity Diagram , Attributes Control Charts , Brainstorming , Capability Analysis , Cause & Effect Diagrams , Check Sheet , Control Chart Interpretation , Flow Charts , Force Field Analysis , Histograms , Nominal Group Technique , Operational Definition , Pareto Diagram , Relations Diagram , Run Chart , Sampling , Scatter Diagram , Systematic Diagram , Variables Control Charts
$90

Hope it helps.