Is it possible to install Xcode 4.3.2 on multiple macs from a single download?
For members of the developer program, Xcode can also be downloaded from Apple's site, without the App Store. I know you don't want to do another download. I'm just mentioning this because the download you get from there is just a disk image with Xcode.app in it. To install, you just drag that Xcode.app to wherever you like, just like any ordinary Mac app.
That strongly suggests to me that you can just copy the Xcode.app that you got from the Mac App Store, too. That said, it may also try to download additional things. For example, doc sets and the Command Line Tools component.
As @KenThomases mentioned, Xcode can be downloaded outside the App Store. This is the recommended approach if you want to deploy it on multiple Macs without the hassle of Apple IDs.
Plus, there's an app for this now: xcode-installer gem