Incase anyone doesn't know of them, here's a list of places you can search to find a link on game nights.
Usually between them all you can get a quality stream.
NBA League Pass is really good if you can afford the £60. Great quality and you get every single NBA game (and the ability to watch it again for 24 hours). The address is Welcome - NBA League Pass Broadband.
Also, for non-live stuff there are two great sites I found-
BBALLVIDEOS - Coverage Of The 2009 Eurobasket - says Eurobasket but it actually has everything NCAA/NBA/Euro (use firefox and download the 'skipscreen' add-on to get around megaupload)