Hi Colette,
If you have a podcast, you should definitely be posting it to as many good quality directories as possible for the best exposure. This includes iTunes. 90% of my downloads come through iTunes. Listing your podcast in iTunes isn't too difficult. You do need iTunes installed on your computer and you need to have an account. Once you have that done, here is some information from Apple regarding feed submission to the Apple iTunes store:
http://support.apple.com/kb/HT1819
Also, if you aren't using Feedburner already for your podcast, I would suggest setting up your podcast feed through Feedburner and submit that URL to iTunes for your podcast. I recently created a video showing how to setup a podcast feed using Feedburner. I think it's in this multimedia marketing section here on VAF.
If you have any questions or need help, just let me know!
Darlene