"My computer only has a VGA connection for video, is there anything I can use to go from VGA to HDMI for my HDTV?"
I'd typically suggesting purchasing a video card with DVI-out, rather than using your current VGA card, in part because the new video card will very likely also have additional video RAM, as well as being able to support native HD resolutions, but if you really need a VGA to HDMI adapter, such components do exist. My favorite source for HDMI cables and other cabling needs, Monoprice, is a good place to get what you are looking for.
Monoprice sells a VGA+RCA to HDMI solution that allows you to take both the video from your VGA connection and your sound card output, passing them through a converter box and outputting HDMI on the other side for about $40. I haven't personally used this device, but similar devices have been known to end up with audio and video slightly out of sync, so it should work well for displaying your computer screen, but might not be ideal for playing video from your PC.

