Open the http.conf file found in your /wamp/bin/apache/Apache2.2.17/conf/ folder.
Search for the line that shows Listen 80 and change it to Listen 81 or whatever port you want to change Apache to.
Save and Close the file.
Open the wampmanager.ini file in the /wamp/ folder.
Search for localhost and when you find the lines that shows Parameters: “http://localhost/”; Glyph: , change the last parameter to http://localhost:81/ or whatever port you have changed for Apache. This may come up in multiple places. This is to make sure that wamps links work properly.
Save the file and close.
Do the same thing with the wampmanager.tpl file and you are done