I am interested to learn from the community what software or other mechanism people use to address software project estimation needs and cost/effort actuals analysis, as well as for project accounting.
Software is a tool not a solution.
Microsoft Project is used for project management and project task management (two different things) however whether that is successful depends on the "processes" that are in place at the company.
A company that is not committed to creating and maintaining process control will never succeed at project/task management in any meaningful way. The company must be committed enough to make successful implementation of process control a significant factor is measuring success of managers and lower level workers. The company must also have the buy in of a high level manager to insure compliance. One proven successful way to do this is to base employee reviews in a significant way on the employees use/compliance with existing process controls.
Naturally for it to be really successful the company must also recognize that those using the process control procedures must have significant input in the creation of the processes and also that processes can change over time.