Query about LCD TVs and computers

I'm not very good with computers.
Well, I'm alright with them. I can use them. Software and external devices, games and media etc. I can work out. But when it comes to the more complicated things - the internal hardware, the specifications etc. - I'm lost.
Here's an example.
I'm a console gamer, but would like to move into the realm of computer games once more. My computer, however, runs like it's swimming through molasses. I need a new computer. Coincidentally, my old CRT is also rebelling against me. So I need a new TV.
There's a range of HDLCDTVs out there, including a 40" with Freeview, a HDMI port and a "PC Port" (unspecified). I'm assuming that this is the one that would allow me to use it as a PC monitor. I've read and heard that the encoding for PC monitors would allow this, but common sense (or paranoia masquerading as it) says there must be a catch. I don't know if there's a minimum specification or graphics card power I need, and if the Freeview feature would cause any clashes.

tl;dr: how do I used TV as monitor?

you need a video card that supports TV tuner.

you need a video  card that supports TV output.

"pc port" is generally an angled D with 15 holes in it, usually blue.  this is the old standard for monitor connections and is fine for short distance connections.  using this connection only would mean that the tv is your main monitor. e.g., you may have input1/input2/input3 etc, and one of them uses that pc port.  if you just want to use a tv as a monitor, thats probably enough, but youll still have to plug other devices into it as well to watch tv/consoles/etc.  otherwise, you need to listen to >>2 and >>3 for real tv functionality.

How would I know if my Video Card supports these things? Would it be advertised, or is it taken for granted?