It has been 10 years since Tom Peters wrote an article in Fast Company called, "Brand You", but the principles of personal branding (read: reputation) remain the same. Lawyers especially rely on their reputation as a niche specialist for referrals and new business. Read the article here.
One way to measure your brand is to see how you are perceived on the internet. This article has several tips on building your on-line presence and an on-line assessment of your on-line brand. What's your Google IQ?