As well as Myst, Mean Hamster Software is porting the second game in the Myst series, Riven to the Pocket PC.
"Riven, even larger and more beautiful than Myst, contains more live-action characters, and full-screen movies. It is considered the most mind-challenging chapter in the series.
Atrus has sent the player to Riven to rescue his wife Catherine, and trap his father Gehn. Along the way, the player's explorations include an underwater shuttle and a magnetic levitation high-speed tramcar that hovers over its rails."
There are no screenshots available at the time, and the release date and price are not available at this time. It looks like this is a great time to have a Pocket PC if you like the Myst series!