NSString *aNSString; CFStringRef aCFString; aCFString = CFStringCreateWithCString(NULL, [aNSString UTF8String], NSUTF8StringEncoding); aCFString = CFXMLCreateStringB
They are equivalent, so you can just cast the CFStringRef:
NSString *aNSString = (NSString*)aCFString;
For more info, see Toll-Free Bridged Types.