I've always done manual submissions, actually, I haven’t done a submission for some time now with new sites, basically I just go out and get the site listed in legitimate directories and let the engines come and crawl their way to it.
As I go through the manual process, I notice that many SE's are charging for adding the URL. I wonder if this is what will be the norm as the years go by.
Some SE's used to charge but dropped it due to lack off responce. Most of the big search engines like Google you don't need to submit too as Marc points out, just get a link from a site within Google's index and your site will be crawled and indexed.
To check to see if a site is indexed (or more importantly the page your link will be on) you can click on the cached snap shot of page from the Google bar (if you have it installed) or do a search in Google as follows.