John Allen has an excellent WYD backgrounder today: why the gathering is important, and what to look for in terms of Benedict’s meetings and talks during the event:

Third, youth are critical to a pope’s capacity to lift the church out of the ideological ruts of a given era. Adults tend to become locked in debates over a limited set of issues, recycling those arguments in endless combinations. In the 16th and 17th centuries, for example, Jesuits and Dominicans clashed over competing theories of grace; in the 19th century, Catholic democrats and Catholic traditionalists locked horns over the “Roman question”; today, “liberals” and “conservatives” go at one another over sexuality, dissent, and the authority of the pope. Sometimes resolution of these debates is less a matter of victory for one side, than the capacity to see the entire matter in a new light. That’s what young Catholics have to offer – a fresh perspective, not defined by the categories of the past. In order for that to work, young people have to be willing to invest their energy and creativity in the church. World Youth Day has the capacity to awaken such passion and commitment.

If Benedict XVI wants to challenge the dictatorship of relativism in the West, he’s going to need motivated, well-formed youth, and there’s no place like World Youth Day to assemble his team. The extent to which Benedict XVI succeeds in connecting with the youth who assemble to hear him in Cologne, therefore, should tell us a great deal about where his pontificate is headed.

John also links to what looks to be an invaluable resource – a press pool site of freelance journalists covering the event