Capture Planning offers tutorials and workbooks for business and professional development.

Here is a list of free articles they offer:

Proposal Writing - How to Write a Business Proposal - How to Write an Executive Summary - Proposal Writing for Professional Services - Proposal Management - Red Teams & Proposal Quality Validation - Proposal Process & Procedures - Proposal Training - Business Proposal Software - Business Proposal Tips - Business Proposal Graphics - Oral Proposals and Presentations - Sales Letters & Copy Writing - Government Contracting - Request for Proposals (RFP) - Small Business Innovation Research (SBIR)

An online guide on the DoD Office of Small Business Programs Website. Offers some basic steps needed in order to begin bidding on DoD contract opportunities.