Just one thought re worshipping in the midst of tragedy - since the 22nd February 2011 earthquake here in Christchurch, NZ ... stick to the book.
We are all well meaning, and we want to do the very best we can with helpful words and caring made up prayers and so on. But it is so hard to get words right. My experience is not your experience. My intense conviction that God did not send the earthquake may not be your intense conviction (not because you believe God sends earthquakes punitively or maliciously, but because you believe God is in charge of everything and so earthquake (somehow) fit in with God's purposes).
So it has struck me that if we can bear to gather to worship together in the midst of tragedy then the simplest words to use might be the familiar words of liturgy. Such words are not specifically designed to meet us in our hour of tragic need so they are not condemned if they do not directly help us. Being familiar, such words do not require much listening effort on our part. They can wash over us and seep inside us.
We can take time to think about what to say as our wise contribution to talking about these grave matters. A month or a year from now might be the best time to speak. In the meantime, stick to the book!