Foundations usually have general guidelines for submitting proposals for grants. Availability of funds can be immediate or long term, depending on the foundation's policy. Amounts vary according to stated needs. Corporation funding is usually available in a certain area of education and related to their business. Corporations can consider grants as donations.
Every large city has a foundations center Many school districts or departments offer grants.
Some local or national merchants and religious institutions offer grants. Foundation Grant Index - tells who gave what grants and the geographic areas receiving them. If you know of a grant that is available and that matches your idea for a practicum internship project, consider planning ahead for the funding to be available when you begin implementation. Consider writing for it as you compose your proposal. Basically, a practicum proposal is nearly a complete grant proposal.