Admittedly, I\'m a newbie on the Apple / Mac ecosystem...
On Max OS X, the default install from Qt Disk Image installs to the user\'s home directory (/Users/whoami
Launch Qt Creator once from Terminal, then while it's running right click on Qt Creator in Dock, select Options->Keep in Dock. Or just drag it to change its position in Dock, it'll stay there even after you close it.
If you want it to live in Applications folder, just drag it there. If you press Cmd+Option while dragging to Applications, you'll create alias (shortcut) instead of copying the whole app bundle.