You can watch NBA games via PPLive, PPStream, TVants and other p2p TV for free.

Usually p2p TV clients can be used in Windows only, but pplive has an online player.

What p2p TV channels have NBA games:
-NBA TV
-Guangdong Sports Channel (in Chinese and Cantonese language only)
-Videoland Sports Channel (live and delayed broadcasts of NBA matches in Chinese)
-Zhejiang Sports and Leisure Channel (In Chinese)
-ESPN Taiwan
-CCTV-5 (sports channel in Chinese)

p.s. You can record p2p TV broadcasts using PPRecorder.