These sites provide helpful information and templates for software projects.
NASA Goddard Space Flight Center: Free resources and guidebooks on process improvement, measurement, and software development. Great resource!
Software Program Managers Network: Sponsored by the DoD, contains a wealth of information on software project best practices --- some free downloads.
Institute of Electrical and Electronic Engineers: Main site for IEEE provides access to articles in IEEE Computer and Software journals as well as standards.
Software Engineering Institute: Provides information about the various capability maturity models and technical reports on a wide variety of software engineering and process improvement topics.
Project Management Institute: PMI’s information center. Contains links to project management related topics and information on PMP certification.
Standish Group: Access to a free download of the report "CHAOS: A Recipe for Success"
IEEE Software Engineering Body of Knowledge Project: Free download of the public draft version of the comprehensive software engineering standard body of knowledge.
Agile Alliance: A wealth of free information and links to all kinds of “Agile” software development approaches.
Karl Weigers Consulting: A great resource for links to software process improvement information as well as many free templates and checklists.