QualNet

 Good for wireless network simulation. Commercial product. Fancy interface. Few documents. Supporting forum sucks.

2007/9/5:

After painful code reading, I've known many things about qualnet. I can change something and compile it. However, I still cannot and don't want to write a whole protocol -- that'll be even much more painful!!!

By the way, the official QualNet forum SUCKS!!! I casted several questions there, few were answered, none of them is satisfying. 

So, any question on QualNet is WELCOME here. At least, we can discuss. 

Also, I have some notes about my work with QualNet available on my blog. Hope them useful. 

2007/AUG/1 

To be honest, I don't like Qualnet because it's not open-source.  Compared with Ns, Qualnet's supporting documents and resources are barely little. 

Here I upload some official documents of Qualnet.