The best strategy is to ignore search engine submission completely. Search Engines have what are called spiders, that will crawl the web, following links. The best option is to submit your site to as many free directories as you can. This will ensure that your site eventually gets crawled in a timely fashion.
Be wary of sites that claim to submit your site to "300+ search engines and directories" for free, or $99.99. Whatever the case, these sites are usually automated submission scripts which boast high rankings and gold at the end of the rainbow. I assure you, they do not deliver, and you're out the money. The problem is that it's an automated process (non-organic). The fact is that these directories and search engines change their submission procedures quite regularly, and in reality, it's impossible to keep an automated submission script up to date with thousands of sites. Plus, as we described above, submitting to search engines is a waste of time, since they will eventually crawl your site if you have good inbound links.
There are several types of directories to submit your web site to.
Directory lists provide the latest directories (usually with some statistics about them) that you can submit your site to in your SEO campaign.
A Directory tracker such as Directory of Directories (http://directoryofdirectories.info) can be useful to monitor the directory industry.
Dmoz.org (http://www.dmoz.org) is the human edited directory. In the early days of SEO, it was always suggested you first submit to the dmoz (open directory) project. However, more recently, post 2004, it seems that people are finding their submission waiting in queue for months at a time.
It could take months for DMOZ to add your site. And who knows how long since Google last updated their directory.google.com site. Heck, at the time of this writing the copyright still says 2004 (it's April 2005). Google used to update their directory listings once every 3-6 months, but I haven't heard about an update in over a year.
The main reason Dmoz was so popular, is that if you got added, you got a pretty sweet PR link from directory.google.com within a few months. If they aren't updating the feed from Dmoz, then it kind of defeats the purpose.
However, it doesn't take much to submit to a category, so it's probably worth doing. First, find the most relevant category you can find. And only submit once. If you submit the same site to multiple categories, they will simply reject it. ALso, make sure the category you are submitting to actually has an "editor" (this will be displayed at the bottom of the page). If there is no editor, go up a category, and if the parent category has an editor, submit to that one.
Then wait at least 1 month. If you still don't see your site under the category you submitted to on dmoz.org (http://www.dmoz.org) then you should inquire about it at Resouce-Zone (http://www.resource-zone.com). There is a forum provided that is maintained by the Dmoz editors. You should read the "posting rules" and follow it exactly as they describe. Otherwise, you may get an editor who simply won't bother with a malformed request, and delete your posting.
You can submit a free link to Yahoo!'s directory (http://directory.yahoo.com), it is not known how long these submissions take, or what percentage they include. However, there are many sites that have been approved free. Browse or search for a category, and then once you're in the category topic, you can click the "Suggest a Site" link at the top of the page. They require that you first check to make sure the site isn't already in the directory before submitting.
Instead of categorising sites based on subject matter, Gimpsy (http://www.gimpsy.com) categorises them by the activities offered by those sites. Unlike traditional directories, that view the Internet as a vast library of 'books' offering information and categorising them according to their subject, Gimpsy views the WWW as virtual city and the sites in it are service providers, allowing the visitors to accomplish a task or engage in a desired activity.
It uses complex filtering and natural language querying to attempt to provide accurate results.
Abilogic (http://www.abilogic.com) is a new directory that offers one free submission per domain name. Submission took 1 day to get approved, and allows for your own keyword phrase, title, and description. No link exchange required.
IAG - Free Internet Directory (http://itsallgame.com) - A new general category directory that accepts submissions in just about any category.
Shopping Directory (http://cat16.com) - A high pagerank shopping directory, with reasonable one-time rate for regular links, and yearly Featured Link rate.
Consumer Electronics Directory (http://techaudio.org) - Consumer electronics directory with relevante categories
Best recommendation: "submit" to google by getting an inbound link from a site (or group of sites) with high PageRank (as seen in Google Toolbar)
Yahoo has been competing directly with Google on the search front, as well as online advertising. Yahoo publisher now has a similar product to Google adsense.
MSN has become quite competitive with Google and Yahoo in the last couple of years.