Free directory listing with major search engine
People find information on the web by using search engines. You can submit your website address to any of the famous search engines (e.g. Yahoo, Altavista, Google, etc)for free. Because it's free, they have the right to refuse your website should it not comply with their listing rule. Your website listing will depend on ranking> The ranking is controlled by the search engine and they differs in the way they rank a page.

Pay per click
You can 'force' your page up the rank in search results. But in this case, you pay for the advertisement of your site. The payment can be in the form of pay per click, i.e.. you pay every time a click on the ad is made, or pay per impression,, you pay for every impression of your ad made. Now it is regardless of the ranking but by the price you are willing to pay. Examples of this service are google adwords and overtures.

Pay per impression
You can also pay for every time the banner that link to your website being displayed, regardless whether visitors will click on that link. However the cost can work out quite cheap. Normally you will pay per thousand impression, or 10,000 impression. An example of this service is Web traffic Max, which guarantee 10,000 UK webhits.

Email marketing
You can also publicize your website by email, by sending lots of them. If you can get a lot of email address, you can do so. But how do you get a lot of email address? You can start a mailing list, or submit the info about your website to a mailing list with large recipients. But care must be taken so that you would not be "spamming". Another option is to pay for it, by email marketing agent. An example of this service is Topica.

Hardcopy literature
You can print a lot of leaflets, posters or brochures featuring your web address and distribute it to people. You can also submit your website in newspapers. Of course there is a limit to the effectiveness of this method, but if you have catchy domain name, its worth it, because people can remember it even at a glance.

Radio/TV
Of course you can pay (a lot!) for your website to be advertised on TV and radio. Normally those businesses with a lot to spend would do this. Again, catchy domain names will help a lot in this case.