Testing multiple iOS versions in Simulator

How can I test multiple iOS versions in the Simulator? I can only seem to test iOS 4.1. I would like to be able to test 3.x v开发者_如何学Cersions in the simulator as well.

---

Cocoa with Love has a good post on how to do this

To allow simulation in 3.1.3, you must install an old version of Xcode. If you are a registered iPhone developer, you can download Xcode 3.1.4 for Leopard with iPhone SDK 3.1.3 or Xcode 3.1.4 for Snow Leopard with iPhone SDK 3.1.3. Be careful to install these in a different location to your Xcode 3.2.3 with iOS3.2/iOS4 (either select a different hard disk or rename your existing /Developer directory before you install).

---

In the "hardware" menu are options to change the device and the version.

---

You can install several version of SDK in different path.

To download an older SDK : http://iphonesdkdev.blogspot.com/2010/04/old-versions-of-iphone-sdk.html