Having a good professional website is highly recommended. It is your way to promote your knowledge, skills and experience.
Your website should be content rich, easy to navigate, quick to load and consistent with the image and you wish to portray.
However, having said that, if you don't spend time to optimise your website, it will remain invisible. You need to optimise your site to achieve good search engine ranking, you should submit your site to the search engines regularly and you need to make sure that your site is listed with one or more of the major directories such as Yahoo.
Look for other freelance sites to list your details, such as elance.com and encourage people to look at your site with offers of free white papers etc. Make sure that you can retain the details of people that visit by including a respinse mechanism, such as a contact us form.
Once you have your website up and running, refer your potential clients and agents to review it. Again this will help to differentiate you from your competitors.