Labeling based on geographic position?

Hi everyone,
I'd like to label some map features with numbers based on location. I want the feature furthest west to be labeled #1 and have the numbers increase as points go east. Is there a tool that will do this? I have hundreds of points to label so I don't want to do it manually. Maybe there is some process using the field calculator I don't know about that can generate field values based on location?

Thanks!!