How to detect if the UIMotionEffect is supported?

Is there a way to detect if the UIMotionEffect is supported on the device my app is running on?

You can test it like this :

if ([UIMotionEffect class]) {
    // do stuff with UIMotionEffect
} else {
    // UIMotionEffect does not exists
}

In iOS < 4.2 do it like this :

Class theClass = NSClassFromString(@"UIMotionEffect");
if (theClass) {
    // do stuff with UIMotionEffect
} else {
    // UIMotionEffect does not exists
}