SAN News (presumably standing for San Andreas Network News), is a news agency appearing in Grand Theft Auto: San Andreas. SAN News has no ground operations unit in Xbox and Xbox 360 versions, instead, VCN is its placeholder and this is evidenced by the VCN markings on the Newsvan.
The broadcasting agency has its own helicopter, the News Chopper, which can be seen flying alongside the Police Maverick and around the player when a four star wanted level is achieved. The helicopter doesn't affect anything, but Carl can still shoot it down.
For on-the-ground operations they use the Newsvan but, unlike the News Chopper, it is not deployed on the streets based on the wanted level, and can be found driving about the various streets and highways.
It is never revealed if SAN News broadcasts anything other than news or where their studio is. However, a Newsvan can be seen parked outside the Missionary Hill Radio Tower on Missionary Hill suggesting that their studio and broadcasting facilities may be located here.