Sometimes, after installing, you find out that the chosen port number is not the best or preferred number. In my case, an application was installed using the same portnumber as central administration.
This can ofcourse be initiated, by the fact that the final portnumber was not yet known at installation time, OR, you have sharepoint 2010 installed as a standalone installation (you are not allowed to choose the admin port in a standalone administration)
So you want to change the portnumber.
Here is how it is done.
Open the sharepoint 2010 management shell ( yep, powershell to the rescue)
type in: Set-SPCentralAdministration
You will be asked the new portnumber.
Or type in : Set-SPCentralAdministration -Port
It will take some time, but then the portnumber of central administration is changed. Done it several times now, sofar, no issues.