I worked at Intel as an unpaid intern for about 8 months. I didn't get hired afterwards, I didn't really make any great contacts (met some great people though). However, it was one of the best experiences of my life. I might go as far to say it changed my life. It all really depends on what you plan on getting out of it. You should also learn what your responsibilities and duties are going to be before you even start (like any real job). It's your own fault at that point.