How to switch versions of iPhone SDK?

Now that I installed SDK 3.2 for my iPad development, I need to build with the previous version for my old iTouch. Is this possible to switch or do I have to uninstall 3.2, install 3.1.x and re-install 3.2 in a "ver开发者_运维技巧sioned" folder?

If you go to build settings (right click on your project and click info) you can set the base sdk for the project. the setting is right up the top of the list. if you set it back to 3.0 (for example) then you can choose all releases from then till now.