I'm having trouble setting mt new Sony Bravia KDL-40V2500 on time warner digital hd from analog reception digital. I put digital setup on then hit auto program but my tv says no digital stations found. I was wondering if i'm supposed to set this up or its not neccessary.

You need to connect an off-air antenna to your set. Depending on where you live, your local network affiliates may be broadcasting a digital signal; they may even be broadcasting in HD. Once you connect an off-air antenna, your set will scan for the digital signals and determine what you are receiving.

Unless your TV has a QAM built in tuner, you won't get anything from the cable this way. A quick google tells me it doesn't have a QAM tuner, so like the above poster says, get an antenna.

can anyone link me to an off air tuner and how much better would this make my reception. Basically is it worth buying it?

If you get a QAM tuner, you will be able to receive (from cable) only those HD channels that TWC doesn't encrypt. This probably means only your local broadcast stations, and maybe not even all of those. Here, Charter carries only the CBS, NBC, FOX and PBS stations in HD, and not ABC, CW or MNT. To get ESPN HD etc., you need to upgrade your TWC service to a suitable level if necessary, and rent a digital STB or PVR from them.

That said, two current standalone STBs that can handle both QAM (cable) and ATSC (off the air) are the Samsung DTB-H260F and the PrimeDTV PHD-200. Both of them have active threads in this forum, which you should be able to find easily.

Off-the-air reception and what kind of antenna you need depends on how far from the transmitters you are, how strong they are, whether there are hills or mountains in the way, etc. To get an idea, go to http://www.antennaweb.org/ and enter your address, then if necessary, zero in on your exact location using the clickable map. Their predictions are pretty conservative, so try entering an antenna height of maybe 100 feet to give you a more realistic prediction.

The 40v2500 does have a QAM tuner according to the SonyStyle website. My 32s2010 does and it is from the lower level of the same general line.

If you have a clean Cable Signal coming to the TV then you should be able to get some in the clear channels on the auto scan.

Some preliminary questions:
Does the coax cable from TWC come straight into the set? Any filters or splitters between the origination line and your set?

Cable/OTA switch on the set's menu should be set for Cable On.

Digital setup menu auto scan should be able to find something assuming your TWC hasn't scrambled the digital signals.