is there a script when some one sends you a message, like a slang word like omg, is there a one where when they send it, the script recorrects it to you, insted the other way around?

Unfortunately, I have not seen one although this seems like a very possible thing to do.  As you likely know, Messenger Plus! 3 had a feature that could replace incoming/outgoing text.  In Messenger Plus! Live, you can only replace outgoing text via the Preferences panel.  I've included those instructions for you below.

Replacing Outgoing Text Using Messenger Plus! Live:
1. Open up the Main Windows Live Messenger Window and Click the Plus Icon and select "Preferences".
2. On top of the "Preferences" window, select Conversations.  On the conversations window, select "Quick Texts" (Left Menu).
3. In the "Quick Texts" page, select the "+ Add" Button.  You are now presented with the "Quick Text Settings" window.  Select the "Automatically Replace Text In Messages I Send" Radio Button, and then type the text you want replaced in the first box, and the replacement text in the second box.
4. Select "OK", Select "OK", and you're done!

I have a very early and crude common mis-spelling replacer script, it loads from a .txt list, by adding your own filtered words it can also do some funky icon stuff with (!VER) and (!SVER) I believe Vikke and deAd were making separate spell checking scripts that could underline mis-spelled words, however they are as far as I know now defunct projects, at least until Stuffplug 3's Scripting interface is documented and released