General overview here. It calls for retiring the Shuttle on time by 2010, new vehicles derived from Shuttle technology, a return to the Moon by 2018, and an eventual Mars mission using the same vehicle.
It isn't perfect, and the price tag is
somewhat prohibitive. At least it gets NASA out of the continual cycle of launching only to low earth orbit and coming back, which is the most costly and dangerous parts of getting off planet. While it doesn't come right out and say it, the plan effectively admits that the Shuttle was a dead-end detour from Apollo, and gets back on the Apollo route to the moon while salvaging what it can from the Shuttle.
I would like to have seen the development of an early warning system to map and track all Earth-crossing objects, something that is currently being left to amateur astronomers as far as I know. It would be expensive, and I'm not sure what we
could do to prevent a collison if a large object were found to be coming our way, but it would be a shame if humanity were wiped out because nobody wanted to foot the bill.