A while ago I linked to solving Sudoku with SQL

http://www.noelwatson.com/blog/PermaLink,guid,0bb39397-b60f-4448-8493-51f2c88f5443.aspx

Now Steven Toub at MS has come up with a Sudoku app written in .NET

http://msdn.microsoft.com/mobility/tabletpc/articles/techart/default.aspx?pull=/library/en-us/dntablet/html/tbconsudokusamplefinal.asp

that runs on XP Tablet 2005 edition.

http://www.microsoft.com/windowsxp/tabletpc/default.mspx