What is the cheapest way to upgrade from OS X10.4 to 10.6? I have been living in the past, and it is finally catching up to me.
What is the cheapest way to upgrade from Mac OS X 10.4 to 10.6?
Spend the 30 bucks to get the 10.6 DVD and then use it for a clean install.

There's no reason to buy 10.5 so you can "upgrade" to 10.6. The 10.6 DVD is exactly the same as all the other release DVDs.