VozMe.com is a free web based tool to convert text into MP3 audio. VozMe converts the text you type/copy to a textbox provided into an mp3 file, which can be downloaded and used anywhere. You can also integrate VozMe to your websites, blogs etc. VozMe also provides a Google gadget to add to your Google homepage (iGoogle).
I am not very happy with the quality of the audio. I have tried the text-to-speech conversion using Microsoft Agents. I did not find VozMe any better than Microsoft Agent in terms of speech quality.But VozMe plugins are really easy to use and integrate to your page.