The Landau is your basic case which provides all-around protection (with screen protector) without limiting access to any of your ports or buttons.
The Plus is a more rugged case which covers the entire non-screen surface of the phone. ezButtons are built into the case, which are essentially areas which have extra silicon padding. This allows you to press on specific areas of the case and have the desired button be activated. Your iPhone’s screen will be protected by a standard static screen protector.
Both cases will be available in Frost White, Onyx Black and Cool Blue. The ezSkin Plus is expected to run $19.99, while the Landau will be $5 less. Both are set to ship on July 8, 2008.