How do i enter public rooms in yahoo 7.5 messenger?

well, i downloaded latest messenger of yahoo 7.5 and i tried to enter the room but i found no way.it was only after i requested to a person in my friend's list to send me an invitation,then only i could enter the room.i found no gateway to the public room in the yahoo messenger with my naked eyes.so i am very confused. please help me.and yes one tjhing more , what is this yahoo elite services.people make use of this services and they post many starnge pictures in the public chatting rooms. please hel me solve my problem. i will be great ful to you thank you.