I have to admit that I am one of them and I'm not proud doing it. Thus, in this year 2011 I am set to use only legitimately acquired software. I am a software engineer by profession and I really understand how malicious is the effect of software piracy. At the current moment, other than my daily job, I'm also working as a software development consultant on a part time basis for another company. My concern right now is that I'm indeed using software to earn income. From a Islamic perspective, software piracy is like stealing and income for the use of it is non Halal. I guess I just realized why I'm always getting sick. So, the next thing is, I'm going to legally purchase all the required software for my business.
a post in a forum about fatwas on software piracy: