Are there any free standalone presentation tools that shows which keys are pressed on screen?
KeyCastr is not available as build for users without Xcode. Only a community fork (git://github.com/bignerdranch/keycastr.git) is working on OS X 10.7 (Lion) and 10.8 (Mountain Lion).
Mouseposé is commercial.
Related to the Windows 7 Question: https://stackoverflow.com/questions/3529329
Best Answer
OS X comes with such a tool.
To activate it, you should go in
System Preferences
-->Keyboard
and selectShow Keyboard & Character Viewers in menu bar
, see screenshot below.Then in the top menu bar, ext to the clock, you should have a new icon.
Click on it and select
Show Keyboard Viewer
, now each time you press a key, the Keyboard viewer will briefly display that key. You will have something similar to this:I hope this was what you were looking for.