According to a post on HardMac, OS X Lion might be upgradable to Lion Server through a simple paid update via the Mac App Store. This was uncovered by a French reader who apparently has access to Lion help documents not available on Apple’s US Servers.
Apple either took down the support document in question or it never existed in the first place at least on Apple’s US Help documents server…In fact, there is no reference to Lion Server at all in the Help search menu. Nonetheless, upgrading to Lion Server through the App Store wouldn’t be too surprising considering the consumer-level Lion will be installable through the Mac App Store too.
A provided screenshot (above) shows the supposed support document suggesting that the server application will be available on the Mac App Store, and once it is purchased it will be available in the Applications folder. Users will then open the Server application to set up the software.