The Colorado Department of Revenue is holding a sales tax law fundamentals seminar in Aspen from 9 a.m. to noon Sept. 30 in the Rio Grande Meeting Room. The class is open to the public and offers information on common sales tax topics to help businesses remain in compliance with Colorado tax law. Pre-registration is required. Visit http://www.aspenpitkin.com and click on "CDOR Sales Tax Class" for more details.