Not likely. Blizzard primarily sticks to the PC. Starcraft 64 for example, made by another company. And with big games being developed now (World of Warcraft, Warcraft 3), we probably won\'t see a Blizzard game on the PS2 for a while unless they have another company doing it.
As for the Xbox rumor, pretty much like the Square rumor. Keeps popping up, yet nothing comes out of it (though, I do think Square will eventually be on the Xbox [via FF11] the official announcement, or confirmation hasn\'t materilized despite tons and tons of rumors on this subject).