There are many ways that each clue may refer to the location of the placemark. These include references to countries, famous landmarks or longitude/latitude. You may need to use other online resources (such as Google or Wikipedia) to help you with harder clues.
Unless the clue says otherwise, the placemarks will be in the Google Earth layers, so make sure you have these selected.
Clue 1:
This clue is not too difficult,
I've made it easy instead.
There is an 'i' at Nelson's Column,
in front of a bus that's red.
Once you have found the placemark, click on it and go to 'Click here for the post'. The date & time that it was posted gives the name of the page with the next clue.
For example, this placemark was posted at 09/20/03 09:07, so you should go to http://www.losethegame.com/hunter/0920030907.htm
Please type this address into your web browser to find the second clue.