A link to the NEURON code for the paper
Hao J, Wang XD, Dan Y, Poo MM, Zhang XH (2009) An arithmetic rule for
spatial summation of excitatory and inhibitory inputs in pyramidal
neurons. Proc Natl Acad Sci U S A 106:21906-11

is available on the page:

http://www.ion.ac.cn/laboratories/int.asp?id=54

with the name E-I-Integration-NEURON.rar