Deb,
What great questions. Let me answer them in order and give some helpful research suggestions.
First, any investment company you are considering or already investing with should be able to provide a prospectus and other written information that tells what the company invests in and the object of the fund or investment. So when an investment company asks your level of risk, you want to ask them what is being invested in at each risk level and ask them for written materials that show this. You want to pay particular attention to the list of fund holdings.
Second, as far as I know right now, each social fund follows its own set of guidelines to screen which companies it invests with. Again, these screening criteria must be set out in a prospectus or written material. Most of this information is available online at the company's website.
Third, I have yet to find a consistent ranking system. There are various financial magazines, such as SmartMoney, who will rank social funds based on performance. To find funds that are ranked on their social responsibility, you will need to check with some of the social and ethical organizations. I've found rankings through crocodyl.com, ranker.com, and PETA. PETA does a very nice job of listing the companies that do not cause cruelty to animals.
Finally, these same sites can offer their criteria for why they judge a company worthy of being socially responsible. Plus, fund company prospectuses will list their criteria of for choosing companies. Much of social investing is still reliant on our own personal judgement of what is socially acceptable.
I hope this answers your questions. Please feel free to ask me more or to clarify.