The situation in Mumbai hasn't yet wrapped up, with hostages being still held at the Oberoi Hotel. I've been watching streaming video from CNN/IBN, so hit the link if you want to track the situation.
It seems that several terrorist teams arrived on small Zodiac-type boats which may have been launched from a cargo ship anchored off Mumbai. All signs point to an operation by the Islamist militant group Lashkar-e-Taiba, which is responsible for a long string of terror attacks in India. The main axe they have to grind is India's sovereignty over parts of the disputed Kashmir region, yet the terrorists are reported to have specifically targeted American and British hotel guests for capture.
In any event, this style of terrorism truly represents a shift in tactics from the usual random bombing attacks and is unlike anything we've seen in recent years.
Update: Fixed the cargo ship link...it now links to a longer article, but the mention of Indian navy boarding a cargo ship is further into the article.