When you launch your website, you probably want it to be found quickly in the search engines. Although most search engines have some sort of "Add URL" facility, this usually achieves nothing. Search engines generally discover new pages by following links on existing pages. There are hundreds of sites that allow you to place a link to your site for free and this article will give you a few places to start.
Hotfrog - if you're outside the USA, check their International sites link at the top right
Search for "business directory" and you'll get a bunch of listings. Just stick to the free options as the goal here is to simply get a link.
Local Listings - if your organisation services a local area, you can list in Google Places and Yahoo Local. Also check if there is a specialist local site in your area.
News Sharing Sites - such as Digg, Mixx, Reddit
Bookmarking sites - Delicious, Mr Wong
Article sites - write an article related to your industry and include a link to your website - Ezine Articles, HubPages, Squidoo
If you follow the above steps, your site will get indexed much faster.