Some Macintosh programmers like to call the REALbasic development environment the heir to HyperCard. I'm new to programming, so I don't know about HyperCard yet. Those of you new to REALbasic (like I am) can read about Michael Swaine's REALbasic for Macintosh.
MacPlaces Mac OS X dev. resources
Download REALbasic: Software, documentation, plug-ins, and sample projects.
REAL Software's Home Page for REALbasic 5.5
MacTech Journal: Rapid Development with REALbasic
REALbasic Magazine for REALbasic Developers