What is a good guideline for pricing comps and spec work as well as hourly rates and flat fees? And what are some standard policies I can use to protect my work?

As a guide to pricing comps, I normally charge full design rate. The reason being, is a comp takes as long as the final art in most cases. The idea, creative direction and set up is all in place even when designing a comp. As for spec work, that is always free. I do not recommend ever doing spec work unless you feel that you stand a chance to get the job. Chances are that the prospective client will take your idea and take it someplace else for cheaper. About 98% of the time, I do not touch spec work. If I feel lucky or I know I could get the job, I will do a job on spec. As for an hourly rate to charge, that will all depend on your skill level. I bill between $60 and $100 an hour for design or comp work. My suggestion is to never go below $50 an hour; you have to run a business and anything less will not pay the rent. For some ways to protect your work, you will need a contract, and possibly a copyright ownership agreement.