Comcast may your lineup online at http://www.xfinity.com/Customers/Clu/ChannelLineup.ashx
or https://customer.xfinity.com/local-channel-lineup, but the format is not very good for printing.
If an employee does not post a lineup for you here . . .
Service Centers should have printed channel lineups. Check locations and hours at http://customer.xfinity.com/service-center-locations to pick one up, or call Customer Service at 1-800-Comcast and have them send a lineup to you.