Getting listed in link directories can help you to get indexed in Search engines. Getting listed in a link directory doesn't mean getting higher positions in search results. Link directories aren't also search engine directory.But it can give you a valuable back link to your site.
www.dmoz.org is an Open directory that can give your site a back link from a high page ranked site. This directory is run by volunteers and getting listed to it is free. You should submit your site in this directory if you have lot enough good content. Submitting your site in this directory doesn't mean your site will be listed must. As it is run by volunteers it takes time to get your site reviewed. Sometimes it takes a month or longer to be appeared in that directory. If your site doesn't appear after a month don't keep submitting your url there. Nothing to get frustrated if they never list your site. Getting listed there actually give you nothing but a valuable back link. With your good content you can still make success without that back link.
I have given here a list of some link directories where you can submit you site for Free.
http://www.chiff.com/
http://www.busybits.com/
http://www.spheri.com/d/
http://www.exactseek.com/
http://searchsight.com/
http://www.worldsiteindex.com/
http://www.webworldindex.com/
http://www.gimpsy.com/
http://www.somuch.com/
http://www.abilogic.com/
http://ajooja.com/
http://www.illumirate.com/
http://directory.r-tt.com/
http://www.clickey.com/
http://www.addnewlink.net/
http://www.bigguide.net/
http://www.ddsx.com/
http://www.arakco.com/
http://higherengineposition.com/
http://www.hrdw.net/
http://www.iextreme.info/
http://www.cyber-find.net/
http://www.info-listings.com/
http://www.linkstraffic.net/
http://www.network-room.com/
http://www.plentylinks.com/
http://www.submit-link.info/
http://www.findseekweb.com/
http://www.blogdirs.com
http://www.blogsearchengine.com
http://www.blogarama.com/
http://www.blogcatalog.com
