[header] How to cope when you both like the same guy and he might like you [title] Be honest about the situation. [step] It might be scary or intimidating, but put all of your thoughts and feelings on the table. If you really like this boy, tell her. 
If he's hinted or flat out told you that he returns those feelings, tell her. While it may hurt your friend at first, it will feel worse if she feels like you've lied or left her in the dark.