iPhone OS 4.0 Multitasking Can Be Enabled on Pre-3Gs Devices With Simple Config Change

It's certainly exciting that the iPhone is getting multitasking… but with only the very last generation of iDevice's supported, a lot of people are going to be left behind. Even Apple seemed a little bit embarrassed not to be rolling multitasking out across all devices.
Presumably, the issue is one of horsepower, but not complete [...:]