You can start looking at Auzentech.
Many video cards with HDMI output only have a "passthrough" that doesn't use the videocard. Only certain audio formats will work and you also have to toggle your audio device (so games and Windows sounds don't work. For example, I need to toggle to "ATI HDMI" from "Creative Audigy".)
With a receiver you might be better to just run the audio TOSLINK or Coax digital cable and then run the HDMI cable into the HDTV (for video, you can use a DVI->HDMI or HDMI->HDMI since you only want video).
I don't know what TV you have but if you use a normal video HDMI input your resolution will be constant, usually 1920x1080. You can't choose a Fullscreen resolution for games. To use an HDTV like a monitor it must have a "PC" input such as: "VGA-PC", "DVI-PC" or "HDMI-PC". Again, HDMI Video inputs are different from HDMI-PC inputs. Very few TV's have HDMI-PC inputs.
My dad's HP laptop has HDMI. I hook it up to the HDTV (1920x1080), switch the audio to HDMI out (though in this laptop the audio IS hooked up to the sound card basically manually switching just mutes the laptop speakers and enables the HDMI's LPCM audio output).
Anyway, hooking up a computer to an HDTV can be tricky. To summarize:
1) You need a "PC" HDTV input to be able to change resolutions. The normal HDMI inputs are fine for watching video etc. Mainly you want the "PC" input for games.
2) You need HDMI and a supported HDMI/HDCP video card to watch BluRay. (Slysoft has an HDCP bypass through software I believe so you can use VGA.)
3) HDMI audio can be tricky on the PC side. Generally, the best way is to have a video card that supports SPDIF->HDMI like the GTX275. You also need to ENABLE digital output via SPDIF in your audio settings/software.
4) Receiver are a good idea. Generally, passing the receiver just the digital audio and then passing the video directly to the HDTV is easiest.
5) Another option is VGA + 3.5mm stereo audio.
6) Some newer audio cards have a Virtual 3D mode for stereo headphones. It works very well.