Your first stop in Danang should probably be the Cham Museum (Båo Tàng Điêu khác Chăm). This museum was built by the French and houses many find sculptures collected from the ancient monuments of the kingdom of Champa. The building itself is rather unique, being mostly open air. Most of the collection is actually built into the museum's structure so that you see items in some degree of context.
Although the museum is really quite small, you can easily spend a couple of hours here. Be a little wary of the many "guides" both inside the museum and out.
Admission to the museum is 30,000 Dong (-30,000.00 USD). The museum is open every day from 7:00 am to 5:30 pm.