How to Set up SSRS Web Services to run under another port than 80? What steps do I have to pace to run Web Service URL and, Report Manager URL, under another port rather than 80? (DBMS is SQL Server 2008R2 and OS is WIn Server 2008R2).
The port can be configured in SSRS Configuration Manager. This will have been installed on the machine when you installed SSRS.

Check this and this BOL articles for all the details.