Please see the picture to find the Chinese Symbol for Best Friend.
What Is The Chinese Symbol For Best Friends?
This is how it looks in Chinese...
I do not have any idea. I mean I am not very much into the Chinese culture. I will recommend http://www.chinainfoonline.com/, Hope that will be beneficial for you.
Best friends means "最好的朋友" (zui hao de peng you) in Chinese. Zuhail's answer is generally right, but it's not a simplified Chinese character which stands for "挚友" in stead.