You can log into MSN Messenger in Appear Offline mode using Jnrzloader. None of your contacts will have noticed you logging in. By hiding so, you can:

1) Change your nickname prior to showing the "... has just signed in" popup alert;
2) Switch from invisible mode instantly into Busy (or any other status);
3) Block people you don't want to talk to, before you show up online.

To get this addon, go to our download search and enter JnrzLoader. From the results, pick the one that matches your version of MSN Messenger (see the number in Help > About MSN Messenger)