Let's get the depressing bit out of the way. Publishing for free on a website is a thankless task. The web is littered with sites on which beautifully-designed games languish. So you have an uphill struggle. You can't just publish it online and hope people will find the way to your site.
That doesn't mean that you shouldn't do it. It means you need to work hard on getting your game out there.
For inspiration, look at Lady Blackbird, a very successful freely released game. What did John do to make this game work? I'd suggest the following:
- The graphic design is beautiful, so it's something you want to play.
- He designed the game itself well, so that people enjoy playing it.
- Before publishing, he built up many relationships online, with people who then played the game.
You can do all those things. Make your game pretty. Design it well. And exploit any online relationships you have, asking them to promote the game. (For example, you should be sending private messages to me and Brian, politely giving a link to the game.)
Here's a fourth point, which John Harper didn't actually do before releasing Lady Blackbird, but which you should:
- Playtest your game a lot, at conventions and with local gaming groups, and
- Once it's released, play your game a lot, at the same places.
So, have you playtested your game? If so, you should have a little community of people that know about the game and are enthusiastic about it. Use them. If not, playtest more. Playtest it to death. It makes your game better and it builds that little community.
And, after you've published it, play it a lot. Play it with your local gaming group. Play it at conventions with strangers.
So, to answer your questions directly. How do you package it? There isn't one answer, but a beautifully laid-out PDF is one tried-and-tested way. How do you let other people know about it? It's a difficult question, but playtesting it is a good start.
(On some specific subquestions. Will people download the PDF? Yes, people will download anything, but the greater battle is getting them to play it. Is it easier to read than a website? Perhaps. It's certainly easier to print out.
Should you look for contests and challenges? Probably not, since your game is already designed. Is there any point to posting on social sites? Yes, but those are only tools, and first you need to get people playing. Is it good form to contact game review sites? Yes, contact whoever you can.)