Aww. I'm glad that you remember it fondly, I kind of miss it too. I don't really have any plans to bring it back though; the site it was hosted on (OekakiArt.com) was shut down some time ago, and the oekaki coding and space required for it is not something that I can host on my website.
There are some free Japanese sites that you can make your own boards on, but I don't personally like those, and I haven't looked into any English hosting boards in some years. And even then, I don't have the time to properly mod the oekaki in addition to everything else, so if it did comeback, there would need to be some mods to help keep an eye on it.
I will look into it though, but in the meantime there is the oekaki on AvatarSpiritMedia.net nevermind, they just closed it last week. Uh, hmm. I thought some of the other big Avatar fansites used to have oekaki boards too, but they don't seem to have them anymore either. Well, there is still the Fan Art board on OekakiCentral.com at least.