HR-OneSource (one of Iowa's largest HR firms) has an article in its May 2008 newsletter outlining steps to take when there is office romance in the air. See http://www.hr-onesource.com/articles/May%202008%201_Workplace%20Romance.htm.
Although Jim and Pam from The Office may seem like they are destined to be together, the above article suggests that 80% of workplace romances end. And, when they do, employers have to deal with the fallout. HR-OneSource outlines a number of steps that employers and supervisors can take to make sure they do not end up liable for any work-related claims resulting from a failed office romance.