Bear in mind that I've never filmed a wedding when I say this.

I'd say the one thing that'll show your film up as amateurish is the sound, and it always seems to be everyone's last consideration. Try and find a camcorder with manual sound controls, so that you can keep the sound at a constant level that you're happy with. It will vastly improve the quality of your film. I'm not sure how common manual audio levels are without going into professional camcorders though. I haven't looked particularly hard, but I've already found a Sony one for just over £1000 (the HDR-HC1). Add to that a nice external microphone to reduce any pickup of camera noise.

As for zoom, you just need to ignore digital zoom (you can do it on the computer anyway) and focus on optical zoom. But zooming is another thing that will make your film look amateurish, especially if you're using manual focus so keep it to a minimum if you can.

As for image quality, the bigger the CCD, the better (sometimes referred to as the number of megapixels). 1/6" seems to be the entry level, whereas consumer camcorders seem to go up to 1/4" (which I think is about 2 megapixels). 1/3" and bigger is getting into professional and semi-professional camcorders. 3CCD camcorders have 3 chips rather than one, and produce a better image quality (a 1/6" 3CCD camcorder with probably be better than a single CCD 1/4" camcorder).

But remember all of this is theoretical, so it's probably best to read individual magazine reviews (they have them online) once you've go a shortlist of camcorders. Reviewers will have used more different camcorders than almost anyone on websites like these, so they will usually be pretty reliable with regards to what camera has the best image (and sound) quality. But as far as I can tell, the difference between MiniDV cameras on a normal TV is fairly minimal, especially in good lighting conditions. Look out for how good they perform in low light too, which might be an issue in the reception. Poor low-light cameras will give you a grainy image in low light, which doesn't look too good on a wedding video. Reviews also highlight any little niggles that might be a problem with regards to operating the camera, which you can't get from the specification. I'd personally always trust a review over a list of specifications when finding a camera that'll do the job I want.

As for your other questions, all Mini DV camcorders have DV-out on them to link it directly to your PC. Some have DV-In on them too, which let's you record things back to the tape in the camera off the PC, so look for that if it's an issue. You might want to create a master tape of the wedding, so you can free up the space on your PC, for example. Oh and PAL is just the European standard, so any camcorder (or any other electrical equipment) you buy here will be PAL.

I'd say another optional accessory would be a monopod. It'll give you a bit of extra stability, without having any of the bulk or set-up time of a full tripod, and they're fairly cheap. The last thing you want to be doing is turning their wedding day into a film shoot. But maybe someone who's done this sort of thing before will have more of an idea of specific things that might help you shoot it (I would go fo two camcorders myself, if you can get them, and use the sound off the good one and the worse one to pickup the reverse angle, so if any other guest has a camcorder...)