Think Pascal is available from pascal-central.com. Also, if you Google for "think pascal", you'll get a link to Ingemar's page with instructions to install the patch necessary to run on more recent versions of MacOS.
I'm developing a compiler using Think Pascal, running under MacOS 10.4, even though I have Delphi and FreePascal available (and a PC to run them on). IMO Think Pascal is the ultimate IDE, which all others should aspire to beat. It has debugging tools integrated completely in the environment, with features I've never seen elsewhere. OTOH, if you're really picky about editors then you'll be disappointed. The editor is primitive compared to almost anything available today.
I'm developing a compiler using Think Pascal, running under MacOS 10.4, even though I have Delphi and FreePascal available (and a PC to run them on). IMO Think Pascal is the ultimate IDE, which all others should aspire to beat. It has debugging tools integrated completely in the environment, with features I've never seen elsewhere. OTOH, if you're really picky about editors then you'll be disappointed. The editor is primitive compared to almost anything available today.