1. Add the framework to the project. Build against the 10.6 SDK.
2. Change the compiler settings to target earlier versions of the OS.
3. In “Other Linker Flags”, add “-weak_framework CoreWLAN” (without the quotes).
4. In your code, before you try to use any class methods on CWInterface or whatever, make sure the class exists:

id cwi = NSClassFromString(@”CWInterface”);
if (cwi) {
/* Optionally use cwi instead of CWInterface */
interfaces = [cwi supportedInterfaces];
}

You can even store the class reference as an ivar so that you never have to do more than:

if (_cwi) {
/* 10.6 code */
} else {
/* original 10.5 code */
}

or whatever.

NSBundle * bundle = [[NSBundle alloc] initWIthPath:@”/System/Library/Frameworks/CoreWLAN.framework”];

Class CWI_class = [bundle classNamed:@(”CWInterface”];

Then you should be able to use the normal Obj-C message passing syntax with the Class object instead of using objc_msgSend. (Although Xcode will give you warnings for not having prototypes, you can still send the messages using the standard syntax.)

Also, in your printf statements, you may want to call [[object description] UTF8String] to get a C-string with details on the object.