According to an AP report, the NBA preseason is scheduled to start on Oct. 9th, assuming of course, that a new collective bargaining agreement is reached with the players.
At this point, it does seem quite unlikely that this schedule will be adhered to, as the two sides are not even close to reaching a common ground. Although only a month and a half (comical), the two sides have only held ONE negotiating session. For there to even be a chance of maintaining the current schedule, both sides would have to make a serious effort to come to an agreement early to mid September.
As a side note, all overseas exhibition games have been cancelled.