No, but there is a "One Person Mode" that you can select when making a room. This makes the difficulty you're playing on not quite as hard, and the EXP you get is lowered. It's essentially the same thing as Offline Mode on the Gamecube version, but Episode IV can't be played on One Person Mode outside of quests.
Nu's are so pointless - Eatin_Kirby Nu's are round so of course they are pointless. - BDza
Technically, you can plan offline. You just need to download Sodaboy's Tethella (sp?) server software and set up your own private server to play on. It kind of defeats the purpose of playing though... It's 'Phantasy Star ONLINE" after all.
--- He did WHAT?!?! I'm going to shove a rabid wombat up his...!