Try the Snap which is open source or if you have access to SARscape which is a commercial software is the best, Nest is a old version of SNAP, 

all those software have there own tutorials you could try it.

find the link below  to download SNAP

http://step.esa.int/main/download/

I would suggest you ENVI software for data classification if you are not much experienced on programming languages. Or check WEKA, data mining tool, for data classification as it is faster than envi or other softwares.

If you are experienced on programming, check matlab or pyhton classification toolboxes or library. they have great computing ability as well as broad algorithms for such purposes. Also there are some ensemble methods which can be carried our well for classification of remote sensing data. Since information fusion is still a challenging issue, it might help of you properly.

Best

Thanks a lot both of u...