您可以安装3.2 SDK。 3.0和3.1 SDK包含在其中。

You can just install the 3.2 SDK. The 3.0 and 3.1 SDKs are included in it.

如果您确实需要旧版本，则会有一个链接列表。 http://iphonesdkdev.blogspot.com/2010/04/old-versions-of-iphone-sdk.html

If you really need the old versions, there is a list of links in. http://iphonesdkdev.blogspot.com/2010/04/old-versions-of-iphone-sdk.html