Sharing an AppStore download across computers With the impending release of Lion, I'm wondering whether there is a way to download an app from the Mac AppStore only once, but use the downloaded installer or binary on more than one machine. 

This is especially important for Lion, as I understand that will be a 4GB download. I have two Snow Leopard machines to upgrade, and considering the draconian data caps we have down here in New Zealand, I'm trying to avoid having to perform 8GB of downloads in order to upgrade them both.

Is this possible, or is it a limitation of the architecture that a shared app has to be downloaded via the AppStore on both machines?
Technically, the press says it will be possible and supported for businesses and schools, but you may need to pay for volume licenses. It's just not yet clear if this will be economical or feasible for individual consumers.

In general, you will have to download each purchase once for each mac. Updates will come up as small delta packages to reduce the load on you as well as Apple. Lion itself seems to be getting extra handling as a special case.