When my wife got a new 2009 MacBook to replace her dead 2007 model, one minor irritation I had with the new MacBook was that its wall charger no longer worked with my Early 2008 MacBook Pro. That's no longer an issue; today, Apple issued an SMC firmware update for 2007-2008 MacBooks and MacBook Pros which allows them to charge using the newer MagSafe adapters.
MacBook SMC Firmware Update 1.4 is available either through Software Update or via direct download, and is applicable to the following models:
MacBook (13-inch Late 2007)
MacBook Pro (17-inch, Early 2008)
MacBook Pro (15-inch Early 2008)
MacBook (13-inch, Early 2008)
MacBook (13-inch, Late 2008)
The update weighs in at a paltry 178 KB, but it does require a restart. I can confirm the update works as advertised, because my MacBook Pro is merrily whirring along while plugged into my wife's MacBook's MagSafe port. Hooray for unexpected fixes!