Are you looking for only free streams or would you be willing to pay? Ballstreams.com is what I used last year and they have different lengths of time you can do a subscription for. Otherwise I usually go to firstrowsports.eu for free ones. Their hit or miss for quality
I wouldn't download anything off of the free streaming sites man. If it doesn't let you start streaming right away I'd try another stream link. No sense risking your computer on a preseason game. Now if this was the playoffs...
Never download. Nothing additional is necessary unless the stream is flash and you don't have it installed, which is doubtful. I still would not follow a prompt to download flash either.
Ballstreams have shut down registration. I think you have to be invited if you are not already subscribing...