What are the limits on a Presidential pardon?

Does/Will Bush have the power to pardon any of the corporate bozos who are starting their prison-terms soon or already have started them?

Bill Clinton pardoned his brother (or was it Hillary's brother)... what are the limits to this executive privlege (one that I personally think is outrageous)?

The President has plenary power to pardon anyone convicted for any federal crime.

edit:

Just for an absolutely complete response I should add that doesn't include impeachment convinctions, so a pardon would do nothing to reinstate, for example, a member of the Supreme Court who was impeached by the House and convicted by the Senate.

[edit on 9/26/2006 by djohnsto77]