Is it possible to install iPhone SDK 4 beta and SDK 3 on the same Mac?

I want to test the new OS 4 beta but I still need to update my OS开发者_如何学JAVA 3 apps on AppStore. Is it possible to install iPhone SDK 4 beta and SDK 3 on the same Mac? Thanks!

You can install XCode (and the associated iPhone SDKs) to a folder other than 'Developer', leaving your current iPhone SDK installation intact. You can use 'DeveloperBeta' for example. During the installation, right after choosing which Volume to install to, click on the 'Developer' folder entry and select 'Other' to choose a different folder.

Afterward, make sure you open your desired XCode version and open your .xcodeproj files from there, because double-clicking on .xcodeproj (or other iPhone source files) will probably open the beta XCode version by default.