Proposal Writing Short Course
This tool by The Foundation Center gives step-by-step directions for assembling a proposal. It contains helpful outlines for each specific section of the proposal, including the budget.
Catalog of Federal Domestic Assistance
This premier source of government funding also includes a section on grant writing.
Govspot has a page of links to resources for grant writers.
GrantProposal.com a site devoted to providing free resources for both advanced grant writing consultants and inexperienced nonprofit staff. Includes great tips and advice.