A new grant program to be announced by the University of Michigan today will give needy students $500 to $1,500 a year. Under the program, all needy undergraduates would be eligible to tap into $3 million a year in grants, in addition to other scholarships or loans they might receive. The grants will be awarded on a sliding scale, depending on household income. About $9 million in donor funds will be used to fund the program for the first three years. Special efforts will be made to raise a $60 million endowment to permanently fund the program, said Provost Paul Courant.