There are entire books written on how to become a virtual assistant, so this job is definitely worthy of more research. My advice: Focus on one niche (I just hired Lisa Morosky of VA for Bloggers. for instance.) Also, reach out to potential customers directly and let them know what you can do for them instead of hitting up freelance web sites. Finally, you may want to consider resources such as AssistU. which provides training for up-and-coming virtual assistants.