This is the most annoying part of the whole process: posting your sermon to the Internet. Depending on your Internet connection, this can take ages. There are many places that will host your sermon audio files for a price. I prefer free, though. To do this I use archive.org. This website is technically a library, and works at archiving all types of media. The best part is they will host your original media for free.
One caveat is that you must own all the rights to what you post. Your sermons are probably OK for this, but your worship songs are probably not. Archive.org is a great website for hosting sermon audio for free, but their website interface is not as good as it could be. So be forewarned about that.
You must go to Archive.org and sign up for a free account. Once registered, click contributions, to be taken to your contributions page. Click the “Create and upload a new movie, audio recording, live concert recording, or book” link. Click the share button in the top right. Select your MP3 and fill in your sermon’s information. The more information you enter, the easier it will be for random people to stumble on your sermon. Click choose a license link, I suggest Attribution-NonCommercial-NoDerivs. This will give people the rights to make as many copies as they want, but restricts commercial use and other things. Once that is done, you’ll be taken to the Edit Item Page. Click the update item button on the bottom of the page. You’ll be taken to your item’s detail page. Underneath the VBR MP3 title, there is a link to your audio file that you can copy to your church’s website. There is also a flash player that can be embedded on your website. Click the embed this link and copy the text in the text box and paste it into your website’s HTML.