A slide presentation on whatis new in Leopard in the context of scientific computing has been linked at MacResearch.org by Alexander Griekspoor, European Bioinformatics Institute, Hinxton.
The exceptionally well done slide show, in PDF format, includes some nice photography of the WWDC event held in June as well as an overview of Leopard features that will be of interest to the computational scientist using Mac OS X. (All within the bounds of the NDA all attendees sign for the event, according to the author.)
A high level overview of scripting, Objective-C improvements, Cocoa, language bridges, Core Animation, performance analysis tools, and more are included. This is the kind of high level presentation many scientists would find useful to present to senior management on the capabilities of Mac OS X Leopard for computation.
The link and authoris introduction are at MacResearch.org.