Numbler is a solver that has some special features. You can try it out for free by following the link at
http://www.axcis.com.au/numbler. These are some of the features:

It runs online in a Browser (IE6 & needs .NET 1.1)

Is easy to enter puzzles and you can paste text from this forum straight in, to load up a puzzle.

If you get stuck in any puzzle just use Numbler to provide a next hint

The solver uses logic and it will take you through solving a puzzle step by step

Use this as a tool for learning how to solve Sudoku

It is very quick since it uses logic not trial and error

Trial and error is only used for fiendish puzzles

The Windows version has a Samurai solver as well (5 overlapping Sudokus)

It can also be run on Windows Media Center Edition using a TV and remote control (play Sudoku as a team)
Let me know what you think.