It's an impressive list. It is noted at the link that this is group is larger than the groups which endorsed Kerry and Gore. And, just to give you a taste of the accomplishments of the authors, from my physics perspective:
- Charles H. Townes (Physics, 1964): "for fundamental work in the field of quantum electronics, which has led to the construction of oscillators and amplifiers based on the maser-laser principle"
- Leon Neil Cooper (Physics, 1972): "for their jointly developed theory of superconductivity, usually called the BCS-theory"
- Nicolaas Bloembergen (Physics, 1981): "for their contribution to the development of laser spectroscopy"
- Robert Wilson (Physics, 1978): "for their discovery of cosmic microwave background radiation"
The Boston Globe mentions the endorsement here, which seems to have been otherwise lost in the hysterical reporting on McCain's disingenuous "break".
This unprecedented support is not surprising; as Tom at Swans on Tea noted, McCain has already apparently declared a desire to freeze research funding until the politicians can bring their infinite wisdom to bear on the worthiness of the research.
A little name-dropping: the two Nobel winners I've personally met (very briefly) are on the list: Leon Lederman and James Cronin. I was not surprised at all to see Lederman on the list; he's generally awesome.