iOS SDK has its own NSThread (class reference here) class to handle thread operations, and using it is pretty simple:
In the above source, func_to_call is the function to be performed in the thread and parm_to_func (can be nil) is the parameter to be passed to func_to_call. If one would like to call functions in the main thread from child thread (probably you want to do this when the child thread is going to end and notifying the main thread is required), using the following:
In this line, func_in_main is the function to be called in main thread.
Note: The above method should be compatible with iOS 3.x.