You can download the Macintosh version of UNLAlert from here.

After accepting the application download you should see this,

then continue. Next select the Destination drive,

then select continue. You should then see:

select close and also close the other installer windows.

Next open the Application Folder and double click on the UNLAlert icon.

This should come up briefly:

and you should see the in the dock with the black triangle that indicates a running program.

Next in OSX 10.4 you can control click the icon and select "Open at Login" and from now on you should see the in the dock with the other running programs.

Next in older versions of OSX open the System Preferences and then select accounts.

Select the Login Items tab then press the "+" at the bottom of the list of items. Scroll to UNLAlert in your Applications list select it then select add then close the window and from now on you should see the in the dock with the other running programs.