That's not completely so. I would not suggest using multiple threads. I tried that and it works slower on the iPhone..
The best solution I came to after weeks of struggle is the simple while(running) loop with next steps inside:

1) calculate delta time
2) execute this line of code: while( CFRunLoopRunInMode(kCFRunLoopDefaultMode, 0.009, FALSE) == kCFRunLoopRunHandledSource);
3) update all active screens and objects
4) render all above
5) swap opengl buffers

at #2 the 0.009 is the maximum time to waste on handling system events.
0.009 works best for me because my game depends on input as on nothing else. In your case 0.001 could be good enough. would add a little fps boost. play with the numbers.

HTH,
Alex