An interesting application to organize the worlkflow and tasks is Task Coach.
When we use Task Coach we can create and manage several task lists in an easy and organised way. This is not difficult thanks to an intuitive interface where we can find all options and features easily.
Sort tasks by groups, nest them and manage them your way. Create tasks and sub-tasks to organize them even better.
In short, this a very good application, simple and effective. If you can organize your tasks with a pen and paper, Task Coach will not give any difficulties for you.