The invitation to the first state dinner of the Obama administration was hand delivered over the summer, traveling with Secretary of State Hillary Clinton. She personally gave it to Prime Minister Manmohan Singh of India during her July visit. While this is a state dinner, the Prime Minister's visit is not considered a "state" visit but an "official" visit. The Prime Minister is not a head of state. India’s head of state is President Pratibha Devisingh Patil. Her position has relatively little Constitutional power though she is considered the Rashtrapati, or lord of the realm. The President is elected by members of the Indian parliament and the state legislatures.
This is surely to come up when First Lady Michelle Obama hosts young women from the White House Leadership and Mentoring Program for a presentation on the history and protocol surrounding State and Official Visits in honor of the first State Dinner for Prime Minister Singh of India.