Did Marti Fredrickson sing lead vocals for Still Water in the movie Almost Famous?

No, Marti Fredrickson did not sing lead vocals for Still Water in the movie "Almost Famous." The character of Jeff Bebe, who is the lead singer of the fictional band Still Water, was portrayed by actor Jason Lee, while the actual vocals were performed by musician and singer-songwriter Peter Frampton, along with other contributions from the film's soundtrack.