The second episode of Sam & Max Beyond Time and Space, Moai Better Blues, has been released for the iPhone/iPod Touch and iPad via a universal app.
You can grab it from iTunes here.
A release date for the remaining three episodes has not been set yet, but Telltale seems to have gotten better at iOS releases, so they should be released in the upcoming months.
Thankfully, it seems Telltale's days of releasing one episode for iOS and ignoring the rest of the season are behind us.