Installing on Mac should now be fairly straightforward. There's lots of info here although some of it can be confusing since it still includes X11/GTK instructions:
http://wiki.lazarus.freepascal.org/OS_X_Programming_TipsThis should be all you need to do:
(1) Make sure you have installed Apple Developer Tools from your OS X distribution disk installed.
(2) Uninstall any existing Lazarus. If it's a fairly recent version, you can run the uninstall.sh script. It's generally a good idea to delete the lazarus.pkg from Receipts too.
(3) Run the two FPC .dmg's if you haven't already done this.
(4) Run the Lazarus .dmg.
(5) Drag Lazarus from Applications to the Dock. Click it to make sure Lazarus starts. If not, drag the Lazarus app (not the lazarus executable) from /Developer/lazarus to the Dock.
(6) Optionally you can move the Lazarus folder from /Developer to anywhere else you want. I usually put it in my home folder.
Thanks.
-Phil