Mp3 files, and generators are great for short intros on websites (if you want to use them). I have clients who have signed up for this or that persons audio generator service and using this third party service I was able to add audio to the clients website without any problem.

Most of these services use Mp3 audio format, and although it offers exceptional audio quality it isn't needed for audio which contains mostly spoken material and consumes 10x the bandwidth of other formats such as Windows Media and Real Audio.

If you were to offer me guitar lessons over the web and I had to be able to pick out each note in fast lick that was accompanied by background music you would want to use Mp3. But if you have a 1 hour teleseminar where the content is spoken, Mp3 is overkill. You could include it in this format for those who would like to download the file and burn it to CD for listening to later.

For those that want to listen to the file in real time, large Mp3 files are a nightmare for your users who are accessing the Internet from a 56 dial-up connection. A 1 hour teleseminar could easily exceed 100MB as an Mp3 file, and even if you try and stream it... those with a 56K dial-up connection cannot download the file any faster then 13MB/hr which means a lot of interruptions while they are trying to listen to your file. Then... 13MB per hour is based on an optimal connection, and I've never had a dial-up account where I got over 10MB/hr. This means your listener (with a 56K dial-up connection) may have, up to, a 10 hour download, before they can listen to the file without it breaking up.

For clients you want to stream audio to, the best format, in my opinion, is to use Real Audio, which has support for all flavours of Windows, and installations for Mac and Linux operating systems too. When encoding an audio file to be optimal for a 56K connection, you can turn that 1 hour, 100MB Mp3 into an 8MB real audio file that will allow users with less then perfect 56K connections to listen to the stream in real time, with a lesser chance of having the audio breakup while they are listening to it.

The difference in sound is negligible and it means you will have a lot more happy listeners and pay a lot less for bandwidth.