you wait.
i cannot unblock yahoo messenger
You can actually download Windows Live Messenger for Mac here: http://www.microsoft.com/mac/products/messenger/default.mspx
unblock o.com from my RR email
how
yes you can. go to your blocked list and press unblock next to the person you want to unblock.
You can use FaceTime on a Mac to chat with an iPod Touch (See links below).
If you want to unblock someone you highlight their name by clicking it once and then you click on buddies at the top of your computer and click unblock so and so.
You cant
by locking
you can block (and unblock) anyone bad words end up *'s and in a chat place you can report someone making them unable to send a mesage to you (only then and there)
To unblock an application that has been blocked by a school administrator you will need to ask the school administrator to unblock it giving a good reason why you need access to the application at school.