Hello Vicky ! there are mainly two types of directories , one which do not ask for reciprocal linking and the second which ask for reciprocal linking. those which do not ask for reciprocal links are good source of one way links. DMOZ is one of the best in this category although its a bit slow to approve. If you opt to submit your site to directories which want reciprocal linking then you will have to give them a site on which you can place their links.
I assume that your are new in the field of Internet so I would recommend those directories which do not ask for reciprocal linking.