A few points:
1. It's no different for paying members.
2. Friends are easily contacted, challenge them to a game, this will alert them to your presence (the game can be aborted, if necessary).
3. Try calling their user-name in the general chat-box, sometimes works.
4. Leave a message at their turn-based homepage asking them to speak in the chat-box, you can then right-click on their user-name and challenge them to a game.
I know nothing of Meebo but hope that the above will help you until LiveChess gains more functionality.
I find it really hard to get in touch with people in live chess. Either they are in a game or I am and when i click watch game and it says iv entered chat the other person doesnt see any texts I send... I assume this is another privilage reserved for premium users. Also if one of us challenge the other its easy not to notice it among all the other challenges, or if the other person is in a game. I thought this meebo chat bar would solve this, but it doesnt even appear in Live Chess! Or is it just my comp?