Hello webmasters, i want to submit my site to directories, is it useful for developing back links to my site.
Absolutely, of course it is useful. Look for quality directories that have PR and are search engine optimised. Ensure the category you are submitting to in the directory has quality sites listed and their descriptions written well with no spam. Don't waste time submitting to directories where your link will be placed so deep inside the directory it will never be seen or picked up by search engines. Other useful resources are getting quality sitewide links on websites that have a good PR with a good amount of pages inside the website which have PR. You are here on DP already so search around and see what webmasters have to offer. .
If nothing else it is good to get some initial Pr for your site. Submission services save you time but you usually will get better quality work if you do it yourself.