We all know back links are a big factor in ranking higher in search engines. It used to be simple to get links by submitting to every directory and your rankings would climb. It is quickly becoming more difficult to move up in search rankings. Directories are still important, but it is becoming more important to be discriminating when evaluating which ones to submit to. You need to be selective and in some cases willing to pay review fees.
The first source for an authority link is DMOZ. It is a free directory, but most that submit there do not get accepted. DMOZ is very strict on evaluating websites for submissions. They look for established sites with unique content and completely unique offerings when there are millions of competing websites is difficult to accomplish. Submit here and forget about it. It will be months before your site is evaluated and they will not inform you when it is.
The next best source for authority links would be a few web directories with authority. There are a few in this category that I would recommend. Those being JoeAnt.com, AuthorityDirectory.com, Abilogic.com and dir.yahoo.com. Quality paid directories such as these are wonderful...