I know 10.5 has been designed to fit newer drivers and upgrades for it are available for the existing drivers in my MacBook (late 2006), but when Snow Leopard hits the market, will there be a way to upgrade from 10.4 to 10.6 with the upgrades of 10.5 included?
While not much is known about Snow Leopard at this point, assuming it meets the system requirements, there should be no reason that you couldn't skip Leopard altogether and upgrade to Snow Leopard.
Mac Specs: Black Macbook C2D 2GHz 3GB RAM 250GB HD
Despite its name, Snow Leopard is going to be a standalone OS revision just like the others and won't require you to have Leopard installed as a requirement.