If you're using USB, then it'll probably need a driver which should have come with your camera; might be called a webcam driver. Also, some cameras need you to specify in their onboard menu if you want to output video on usb or firewire. Some video cameras only let you download photos taken with them over usb.
On the other hand, if you're using firewire then they all work the same so you should be able to just plug in and go(play?). When plugged into firewire, the camera should appear in your My Computer; this is the first port of call to see if you can get a picture from it before trying resolume. Anything you can get a picture out of in windows will work in resolume! Open the camera from my computer and hopefully you will see yourself
If this doesn't happen, you can try other applications such as this one i found on the hauppauge site, which will display any working capture device present:
http://hauppauge.lightpath.net/software ... aptest.exe
if you still have no luck, then the problem may be with the firewire card. Check if it's driver is installed (if any) and that it appears in windows device manager (control panel - > system -> hardware -> device manager).
The trial version of resolume is the full version with a watermarked output, i'm not aware of any other limitations and firewire works fine for me on it.
I hope somewhere in these ramblings you have been pointed in the right direction!