You may ask, why should I list my station? The answer is simple. If people don't know that your station exists, they're not going to listen. It's as simple as that. Therefore, you should list your station in every single place you can find.
There are a TON of radio station listing sites. Don't ignore *ANY* of them. Even if you think the site looks mediocre, list yourself anyways. If you only gain one listener from a listing, that listing has done its job. Even the directories that you haven't heard of are essential for audience growth.
Something else that is important to do is to keep track of where you have submitted your station. Write it down. Keep it in a document. Whatever you have to do to remember where you listed yourself. It's important to visit this sites periodically to ensure that your station has in fact been listed, and it's also important to check on your listing periodically to ensure that the listing is still active and working properly. Stations are delisted all the times without notice, so checking on your listings is very important.
When listing your station, do not give them your direct streaming URL! The reason for this is, if you ever change streaming hosts, or if your current host changes your URL/IP, you'll have to resubmit your new URL to all of the directories. A better thing to do is to set up a PLS file (or ASX file for Windows Media) and host it somewhere on your website (example: www.myradio.com/listen.pls) and give them that link instead. This way, if something changes, you simply make the changes in that one PLS file and all of your listings will be automatically updated.
So, the most important question. Where can I list my station?
The Big Three:
iTunes - While iTunes is not nearly as good as it used to be, it's still a great place to list (for now). The requirements for listing with them are always changing. Current requirements and instructions on how to apply are listed here - http://support.itunesinternetradio.com/
Windows Media Guide - As of June 30th, 2016, the WMG service has been discontinued.
TuneIn - TuneIn is probably the best directory you can list in right now. However, it's important to note that simply listing your station on TuneIn alone is not good enough. If you want to attract new listeners and followers, you'll need to be using TuneIn's API. Their API allows you send your metadata to TuneIn which is very important. Most listeners on TuneIn come from users who are searching for a particular song or artist. If you just happen to be playing that particular song or artist, they'll come across your station and you'll gain yourself a listener. For more information about how to set up the API, see this guide: http://tunein.com/broadcasters/api/
Other sites to list your station: (DO NOT IGNORE THESE)
Don't be discouraged that some of these sites are in a different language. Listeners from other countries are just as important as listeners from your own. Use a translator if you need to.
http://www.radiolist.net/ - (send the request to email@example.com)
Going through and listing yourself on each of these sites is very time consuming and it can be a lot of work. Your station will not grow overnight, and it will certainly not grow unless you put forth the time and effort to maintain your listings.
If you come across a site that should be added to this list, please let us know!
Best of luck!