OK i'm wondering i got an NDA already set up, but how to i also protect my members many of them are worried that the project we are working on what i i fired them before the projects release, now i would never do that but i would like to set their minds at ease. what kind of contract should i draw up for this?

If this is an indie project, you need a Collaboration Agreement that specifies ownership, termination, responsibilities, everything.
http://www.underdevelopmentlaw.com/2008/11/collaboration.html
http://www.gamedevkit.com/
http://www.obscure.co.uk/directory/directory-legal/

It can include an NDA. An NDA, in and of itself, has only one narrow function.

If you've formed an actual company and you're actually paying the team members, then this "I won't fire you without good reason" clause can be in the Employment Agreement.