Submitting to search engines is a bit more blown out of proportion than it is necessary. In fact, most of the sites that the major engines spider they get from links on sites they already do spider. Google confirms this in their webmaster Terms Of Service page.

I have successful sites that I never have submitted to any engine.

This is an important factor, not because I am going to tell you not to submit your site to the engines, but because the engines would actually prefer to find your site as a recommendation from another site. Enough said.

Beware of the submission services out there that offer to submit your site to tens of thousands search engines. There just are not that many search engines around. What there are, however, is tens of thousands of Free For All (FFA) links sites out there. This is where your site will be submitted. What these services do is enter your URL and email address into their form and the software takes over submitting your site to everyone else they can find, and they have gazillions of brethren sites all churning out FFA links 24/7. What happens on the site is even worse for you. Your link goes to the top of the category you chose. Soon another site will be submitted and it will go to the top of your category, pushing you down one position. There are generally around 20 positions per category. After a short while you are pushed off the list and that is that. This will more than likely happen the first day, if not within the first hour of your submission. Waste of your money.

No one uses these FFA sites and you will not get any traffic from them. You won't be listed long enough anyway! I used to maintain that it was OK to use these sites as once in a while a major engine would come along and index their page while your URL was there. Then you'd have another listing in their engine. That was good. But over the years these sites have really become nothing more than bad neighborhoods which are bad news to be listed on, and linked out to one.

Directories
Now Directories are another thing entirely. Directories are good. You should do a search on the major engines for your keyword, "add url" (in quotes) and the word directory. Even try it with a "+" in front of your keyword and the word directory. What you get in the SERPs should be good places to add your URL.

What we are looking for here are mini Yahoo! styled search engines, or directories, that are niche specific. I mean, they are targeted at your audience. There are a lot of these around. I'd be surprised if you couldn't find one for whatever category your site is about.

Now, these are small engines or directories, for the most part, and you aren't going to get a ton of traffic from them. At least not usually, that doesn't mean you won't. What you will get is some excellent "one way inbound links" that are nothing short of golden. Mmmm Mmmm Good!

When you find a directory site do a check of the URL, and how the link is structured. Many of these directories are run by database software. The links are pulled out of a database and the URLs are dynamic in nature, meaning they have "?" and "=" within the URLs. These links are really of little value to you. Hover over a link in the directory and look at the bottom left of your browser (if using Internet Explorer) to see how the link displays. If it is simply a domain name, then add your URL to that puppy! If it's a dynamic URL, well go ahead anyway if it is relevant, but you won't get the full benefit of the inbound link.