The NY Times has published several articles about the new museum. This one, "Imperial Roman Treasure Gets a Modern Home", first appeared on April 24, 2006:
Since this city was not built in a day, it is perhaps unsurprising that a plan to house Caesar Augustus's Ara Pacis, or altar of peace, in a new museum has taken 10 years to be realized. Romans, after all, feel possessive about their city. And, in this case, the idea of inviting Richard Meier to design a dazzling white modernist building for Rome's historic center was the stuff of heated debate -- and multiple delays.
Rome's mayor, Walter Veltroni, went ahead with its scheduled inauguration on Friday because April 21 was, at least in theory, the city's 2,759th birthday. But even now, work is continuing on the $24 million glass and travertine marble structure, which stands between a busy highway overlooking the River Tiber and the Mausoleum of Augustus. A 300-seat auditorium and a lower-level exhibition space may not be finished before the fall.
The whole article is here - you will need to be a Times Select subscriber to read it though.