I've created an automatic Sudoku puzzle solver for Palm PDAs. Check it out at:
http://www.palmgear.com/index.cfm?fuseaction=software.showsoftware&PartnerREF=&siteid=1&prodID=104770
I haven't found a Sudoku yet that it can't solve, although the hard ones can take half a minute on a Palm III.
So as not to take away all your fun, the program includes a single step mode, with hints. You can solve as much as you want manually, then when frustration sets in, just press the solve button and see the answer.
One level of undo is also supported.
Email me at Geoffrey.Park@gmail.com before 10pm June 14, 2005 and I'll send you a free copy of the program.
[/i]