Some Multiplayer problems

I can make some cool little online multiplayer games with remote shared objects. but i need to use something that will work 24/7!!!

that isn't the only problem. i am having trouble with other multiplayer game problems too...

I want to know how to make a list of who is online on my chatroom!

i am using remote shared objects (and i already said that). do you use arrays? i have learnt how to use arrays but i don't get how i can store every name in there and how i can take it off the list when the person leaves. do i have to start from scratch???

I HOPE NOT>.< if i do i will get a little annoyed...