by Toldrabald » Mon Jan 10, 2011 4:34 pm
double click on the marker and on the right side of the screen a flyout box will appear where you can enter the name. Note that you have to click on center "pillar" thingy of the marker to show it, not the ones at the end of it.
Btw as this or similar questions are seen quite often: double clicking an ony object in the editor will most likely open up a properties window on the right side with various options, depending on what you clicked on.