Yes, you assign Apache with a different port number from the one IIS is using.

Here broadly speaking, is the procedure for installing Apache on a computer that is running IIS.
1/ During a non-critical period, stop IIS temporarily.
2/ Install apache and select the port number 80. This will install apache as a service.
3/ Edit the apache config file ....from the start --> apache .configure apace.....edit the httpd configuration file. Change the Listen 80 line to Listen 8080
4/ Save the httpd file and restart apache. It will now use the port 8080
5/ Restart IIS. It will continue to use the port 80
6/ To access apache, you will use the url http://<servername>:8080