Think carefully before using *any* site submission service: few do a good job, many do nothing, and most will send you spam beyond the grave.
You do *not* need to submit to Google or any major search engine; all you need is one link from a listed site, and their robots will find you. Free, and no spam.
It *is* worth getting listed in some directories, eg dmoz.org (which automatically gets you into Google and others), and any specialist directories you can find.
It is *always* better, however, to do the submissions yourself - most 'services' will not know the best category to subnmit to, and that can delay - or block - your submission (and may get you labelled a spammer). Also, many directories ignore listings services, which are often considered to be spammers.
It takes little time, it's a learning experience ... and it works!
(For those who *need* good search engine placement, there are many forums (search for 'search engine forum') - just lurk for a few days, you'll pick up some great tips.
True, links are the best way to get noticed. I never submit to search engines, one of my sites has had nearly 300,000 hits and can be found listed anyway. New site, had 300 hits in a few days and again can be found via Google or "whatever" already.