I believe roster cuts will be Sunday at midnight, but I'm not completely sure. wdleehi's call.
Keep in mind: the roster limit is 15 NBA players (including any sent to the D-League) + international players. You can't, however, send a player to Europe unless he's playing there already (i.e., I couldn't send Roko Ukic there, because he's signed to play for Toronto this year.)
That means you can't have (for instance) 15 NBA players + 3 D-Leaguers + 3 Americans you decide to keep overseas.