You will need some sort of tuner to decode the signal and change the channels. Most VCRs have this, but the signal will be poor. Even you did this, your receiver would need to be able to upconvert the signal from your VCR to HDMI. Many can't do this. Most receivers, except for newer ones, need the signal to come in and go out via the same type of cable. The problem you will face is that you are going to be tuning an analog cable signal and are trying to send it to your projector digitally via HDMI. Even if you're receiver can do the conversion the picture quality will be subpar, especially blown up by the projector. But if you are just looking to get anything right now, try running a composite or maybe S-Video signal from your receiver to your projector to view the VCR signal.
For my projector I used to use a an external tuner, commercially called an LCD tuner. It's basically like the kind you can get for your computer but is in it's own box and doesn't need a computer to function. The picture sucked. My next move was to get a tuner card for my PC and use it's output (if you're lucky you might have DVI which you can adapt to HDMI), and the picture quality was as good as I could get with basic analog cable. Finally, I bit the bullet and upgraded to DirecTV HDTV.
Instrumentation & Controls Engineer
Home Theater, Car Audio, PC, Gaming, Photography Enthusiast