hey all..
i want to see alerts of specific contacts come online, i have 100-150 on my list and i want to see the alerts just from a specific group. is it possible?

Right Click > Messenger Plus Features > Events Notification > Create New Notification ?

It is possible, but you cannot group some contacts together and then just set up notification for this group with single click. You have to set up notifications separately for each contact.

You can do like this:
1) Go to Tools -> Options in your WLM main window
2) Select 'Alerts and Sounds' and untick 'Display alerts when contact comes online' option. Also untick 'Contact online' option in Sounds section, else the sound will still be played.
3) Select Plus! -> Preferences and go to Customize! -> Events notifications
4) Click on the 'Add...' button on the right and select the contacts you want to be alerted of when they come online. Ensure that monitoring option is set to 'Notify for selected contacts'.
5) Click Next, select 'User has signed in' option and click Next again.
6) Check 'Display a popup notification when this event occurs' option. If you want sound to be played also, then tick 'Play a sound when this event occurs' option and specify appropriate sound. Also, I have attached original sign in sound converted to a format, which can be played by Plus!

coool
Thanks rix!
using it right now!

Edit: any way to edit the contact picture to the plus alerts like the original messenger?

No, as far as i know, these are Plus!'s own toasts and i don't think they can be edited.

For more information, check CookieRevised's reply to "include display pictures in toasts".