Yes. There is an NBA LEAGUE PASS Broadband free preview which begins the first day of each regular season. It lasts at least one week. During the free preview window you will see a specific free preview option that will allow you to sign up. Go to the NBA LEAGUE PASS site to sign up: http://www.nba.com/leaguepass/broadband
2013-2014 start of regular season free preview dates:
There are additional free previews during the season.