How can I find invisible buddies in msn messenger?

how can I find if a friend is invisible or not in msn messenger?
is there any simple tricks?

To see if they are invisible or actually offline? Um.. message them. Most likely if they are invisible, they'll message you back.

I've done it on AIM before.

pretty easy.ha ha..
I prefer a more complicated route..and I dont want them to know I care for them too..

Do you mean if they are appearing offline or are blocking you?

If you mean appearing offline then I would just message them about something like homework or whatever, something not very personal, so they won't think so much that you 'care for them' (why wouldn't you want them to know that anyway?) but that you just need a quick and easy reply on homework.
If you mean if they have blocked you, then ask one of your friends that you know they have on their contact list if they are online or not.

is there any tricks without letting them know that I am online..
I have seen sites that tell whether a person is online or not..any similar ways

just delete their IDs if they dont reply