I'd like to be able to perform certain actions when the user clicks on an object. Specifically, to connect to a database and read some information about the object, then display that in a window, ideally a form with various types of messages: lists, checkboxes, text etc. Can this be done (has anybody done it) through Unity?
http://www.unifycommunity.com/wiki/index.php?title=Server_Side_Highscores ^^ Database info...
Read info from a database there...
As for outputing to screen... Use GUI, you can have an Exit button at the top of the GUI.
For GUI...
GUI.Label will work, and then you can position it in an "Info" spot on the screen, or you can just have it pop up...
http://unity3d.com/support/documentation/ScriptReference/GUI.Label.html
Good luck, hope this gets you to a start...
When you start coding, post again on forum and people can help you further.
I'm working on something similar to this i'll let you know what i find