How to tell your best friend that you are in love with them?

yes, yes i know, this question pops up a lot, but its different cirstances, ive been in love with my best friend for over 10 months now, and during that time ive helped her through a shitty relationship with her ex bf (which gave me great pain in watching her be hurt as well as wanting her) and now she is in another relationship, its that old adage, you can help others (her) but not yourself, people used to think i was in love with her, but i can ure you its was merely platonic, but now, its different, and i need your help Yahoo Answers as i cant stand this any longer.