TCS
The only way he is going to come close to the performance of his desktop is if his notebook has Radeon Mobility 9600 vid card and a 7200rpm hard drive (most have 4200rpm drives).
A Centrino Notebook with Pentium M, Radeon 9600, a 7200 RPM Drive, and 512Mb of DDR would be an excellent start.
(But it will put a dent in the wallet.)
Take Care,
Richard