the quickest and easiest way is to pay for a directory submission service. these don't cost much. the problem is your url will be submitted to several junk and irrelevant directories and or categories. the best way is to set yourself about 30 minutes to 1h per week and do it yourself. At first, obviously, it's more time
Use some tool for semi-automatic directory submission like digiXMAS Directory Submitter. That's the most efficient way to do directory submissions. All you need is a good directory list. You can start from here: 150 Free General Directories, Fast Approval [01 November 2008]
Yes, paying someone to do it is the easiest. However the good services will cost a little and won't submit to junk directories.
if you want, i sell a software that will help you speed up the manual submission process by up to 500% Its on sale for $25 pm me if you need more information. If you dont want to spend money, there are plenty of free scripts online that do it automatically but google seems to not like when sites use these.
You can choose us and see our experience which you expect to quick enlist you directory on several sites. If you agree, welcome and contact with us.
it's very difficult to choose a good service of directory submission. avoid to submit spam type directories that would damage your sites...