You can do this by tweaking the default start page for IIS. Here is one way to do it:
- Launch Internet Services Manager
- Select "Default Web Site" on the left pane
- On the right pane, look for iisstart.asp
- Right Click | Properties | File tab
- Select "A redirection to a URL" and enter the PCA URL
You can also create your own startup page instead of using iisstart.asp and include links to PCA and CCM user pages there. You can read more on this on the IIS help pages.