iTunes is not a website, its software that you can get at
Once its installed click on PODCASTS on the left hand side, and then down in the bottom right hand corner click on PODCAST DIRECTORY. Then smack dab in the middle of a bunch of icons will be SUBMIT A PODCAST button.
BE SURE To go to 
and make sure your feed validates before submitting it to iTunes. If you are using feedburner you would want to submit your feedburner feed. If not, jsut submit the rss feed from your wordpress (or other blog software that you may be using).