Requirements Management Tools

I use Merlin.

http://www.projectwizards.net/en/merlin/

Requirements management has a number of stages that may be vastly overkill for anything less than enterprise-level software. Do you really need to go through the traditional path of investigation, feasibility, design, construction, test, change management, and then release? Likely, you just need to build a minimum viable product from a strong spec sheet, and protect against feature creep.

For that, I'd recommend you consider a kan-ban type of system, which will provide visibility to management as well as keep your programmers on task. It allows for sprints and feature-set prioritization, while maintaining the transparency that lets you keep management in the loop.

I use youtrack.. it can be modified easily to suit every need..