Hi to all the experts (and not-so-experts like me) on the site. I'm quite new at this singing stuff, and I'm probably (read "almost definitely") not getting any of it right...but I'd like to know if you can hear what I'm doing wrong, and perhaps give me a few tips. Here is a link to a couple of tracks I've "sung" on.

It's heavy rock music, veering towards metal. As you might imagine after listening to it, I often have a tight throat after practices. I'd like to remedy this problem, without losing too much power. I do tend to shout a bit, and I'm pretty sure that's not the way to go, but don't blame me for that - I'm a guitarist who can't get a gig as a guitarist, so I thought I'd try this vocalist lark out and see how hard it was.

(Answer - very...)

I have no technical knowledge as far as singing is concerned, and probably even less talent, but I'm willing to try whatever it takes. Be brutal - and as helpful as possible please! I'm poor, so I can barely afford rehearsal room fees let alone professional vocal training!

Sorry, I don't think the link worked. I'll try again:

http://scrubrecords.com/artists/219/music.php

Ok, Jay, I have listened to your the music on your link and as a classical singer I am no metal expert, but I'd give you the following advice:
for starters, don't put yourself down! Positive attitude and belief in yourself is everything. Consider this: if you don't believe in what you do, then how could your audience?
Secondly, the main thing that you need to take care of is your voice, and that means improving your vocal technique and muscle support. You mention that your throat feels tight after singing. This indicates that you are tensing up in the wrong places, which will probably kill your voice in the long run if you continue doing this.
As for remedies, first of all read up on all the exercises and hints and tips found on the vocalist main site. It's a great starting point. However, I would always advise anyone to seek the opinion of a professional vocal coach as it is nearly impossible to give proper advice without seeing and hearing you sing. I know that this is an expensive thing to do, but I would look at it as an investment. After all, if you are a singer then your voice is your tool. It's an expensive tool because you can't replace it once it's gone. Best take care of it, eh?
Good luck!