How can I get a world clock indicator?

I am also missing same functionality. However, if you are looking for current time at different places then Time & Date indicator applet could be off your help.

To show the current time at different places, follow this procedure.

Click on Time indicator applet -> Click on Time & Date Settings... -> Click on Clock tab -> Select Time in another location checkbox -> Click on Choose Locations..

Now enter the name of the place and wait for applet to search it. Once it returns the results, then select the place you want to display.

Now come out, all places you have selected will be visible in your time applet indicator along with their current time.