As far as I know this tutorial works for every msn client.
1. Run [Cheat Engine] and your [Msn client].
2. Attach your msn client's process to Cheat Engine. (In my case, it's msnmsgr.exe).
3. Open a chat window with a person you're able to nudge.
4. Scan [1] [4 Byte].
5. Nudge the person and scan [0].
6. Wait until you can nudge again.
7. Then scan [1].
8. Repeat [5-7] until you've got a few addresses.
9. If needed, freeze the addresses as value [1] to find out which one is the nudge address.
Have fun and annoy your friends