Job prospects for this year's college grads still look promising, but there are signs things are slowing down. According to JOBTRAK.COM - a job-listing service for students and alumni - total openings posted from September 1999 to September 2000 increased 3.1 percent, down from a year-to-year high of 50.4 percent in March. The average starting salary is $36,429, compared with $36,055 last year. Demand for college grads appears to be shifting from private industry to the public sector. Job postings in sales, marketing, advertising, and public relations are down 16.6 percent; listings for business and management gigs have dipped by 12.7 percent. But postings in the nonprofit, social, and community sectors are up 14.8 percent.