There are actually a lot hints and tips for the PDA version of Plant Tycoon. All you need to do is look at the posts here dating before 2007, or search for a specific keyword (using the Advanced search so that you can set the date range appropriately). There is a very good discussion of the magic plants for the Palm version here to get you started.

There are no plans to change the PDA versions of the game to match the desktop versions.