Comment OS X Server + method of your choice (Score 4, Informative) 460
Apple has a robust remote installation suite with OS X Server, which is darn cheap compared to most other commercial offerings.
10.6 includes a first party version of NetRestore (full system image deployment, similar to Ghost or Flash Archive on Solaris), but most people deploying across a large number of systems should roll their own images with packaged based tools like DeployStudio or InstaDMG:
http://www.deploystudio.com/
http://code.google.com/p/instadmg/
Some other good sites for finding info:
http://www.afp548.com/
http://www.macenterprise.org/