To set the Dail-in property to deny access, you look for the corresponding value, in this case:
"msNPAllowDailin" which is set to TRUE.
In Powershell you type:set-ADUser username -Replace @{msnpallowdialin=$false}
Now when you look at the same value in the attribute editor it displays FALSE.
I haven't tried it but i guess everything that has a value can be changed or edited by the same command.
If you know some others, or disagree let me know.