I'm sure Google will be happy to tell you!
Use your preferred search engine to find free hosts and then send each a set of questions. Then choose what seems to be the best for you based on their answers.
To be honest, you'd find it hard to locate a 'good' free host, since free hosts are often oversubscribed. Another issue with free hosts is that, with more or less anyone being able to sign up without having to pay any money, they tend to attract the less desirable clients.
You're unlikely to find a decently secure and reliable service for free. Don't forget that you get what you pay for - if you want a free host, don't expect much!