Welcome Ray!
Lots of great feedback here so far, here's my input.
Standard Listings are sent out on the 15th and 30th of every month. You don't have to be a paying member to receive the listing, but you must be a member in order to submit a song. That's the $300 membership plan. If you are able to generate music quickly, you might consider upgrading to Dispath for another $125 I believe. This gives you access to the often last minute email list of time sensitive or urgent requests. I joined Taxi in March, and upgraded to Dispatch in April. I love it.
To submit a song you have to upload am MP3 to your the "My Music" section of your web page (which you get when you first join). You enter a title, select the MP3 to upload, pick a music category from a drop down menu (instrumental, rap, country, singer/songwriter, etc.), enter lyrics if appropriate in the text box, and cliick upload. Once you are done uploading music, click "Done Uploading."
You can then click the "Submit Music" link in the right frame of your web page. Here you find the listing (search by category), then click the "Submit to ths listing" link. Note: you can't do this the first time untim you upload music to your account. I was trying to submit my first song and kept getting an error because I had not yet uploaded anything.
Once you click submit to listing, you are presented with a list of the music in your "My Music" library. You click the check box next to the song(s) you want to submit, then submit, you are asked to verify your selections, then prompted to pay your $5 per song fee. Pay, and you are done.
What happens next? It could be days or weeks before you receive an email stating forward or not forwarded. Check your spam folder and make a rule to keep Taxi messages. There's also a link in the right farm of your web page to view your submission history. This is where you see what songs have been forwarded or rejected, and which are pending. You also find critiques here, and if you get a forward you get a little certificate.
the "Peer to Peer" section of the message boards is a great place. The people here are very friendly, helpful and honest with their feedback. Also, before you join, I suggest you browse the "Forwards" section of the forums and listen to examples of successful song submissions to get an idea of the quality expected.
Good luck!