Square director Yoichi Wada recently commented on his company's PlayOnline service and its first major application, Final Fantasy XI. He hinted that players can expect to pay several thousand yen for the Final Fantasy XI software package, as well as a monthly fee of 1000 - 2000 yen (8.21 - 16.42 USD) for the usage of PlayOnline. Final Fantasy XI is currently set for a March or April release in Japan alongside the official PlayOnline launch.
While Square currently only has plans to release the (online only) 11th incarnation of the Final Fantasy series on Sony PlayStation 2 and PC, that doesn't mean that the company has no interest in bringing the game to other consoles as well. Square still shows some interest in Microsoft's Xbox, whose built-in harddrive and ethernet are seen as advantageous compared to Sony's add-on solutions for PS2.