I tried
Skype before and I wasn't satisied with the video quality. May be it was due to slow connection, so I suggest you to try it.
Although I use Skype, I don't like it because it is using p2p technology. The reason for that is that I don't want any traffic coming through my computer and I don't want my chats to come through computers of others.
Many other programs support only low resolutions, so they will be of no help for you either.
Another problem is that a fixed camera gives better details. You will need to keep you camera as steady as possible to get better results. You may also use a tripod or something like this, although I haven't seen any tripods for web-cams.
Using a digital camera attached to a laptop via firewire will probably be inconvenient.