2010 update on text-to-speech read more here
There aren't may text-to-speech application available online. It would be great if it could read you the complete webpage. NPR does it by allowing your to stream content of each page one after another (but then they are a radio station). So why not have website that will read you all the article in the page without having to buy any software.
Bluegrind and new web 2.0 website in beta stage (serious beta stage!) will read you a news article, blog and they claim its like having a personal news anchor reading the news to you every day. It doesn't just stop at your computer, you can take it with you wherever you go.
What are the other Text-to-Speech (TTS) web application out there? Not many but we have found some cool research sites that let you read text. The best of them all AT&T research website. Yes AT&T. This application will read in 15 voices/language, there is a 300 character limit to the text you can input a a given time.
IBM's Research into TTS
This page demonstrates some of IBM's work in unconstrained text-to-speech research. IBM's system generation process is automatic and can be built for any custom voice. From each voice recording, small segments of speech are extracted and stored in there speech database. During synthesis, these speech segments are assembled using specially crafted algorithms to generate any word in the language. Type in your text and check it out.
Oddcast demo website uses sitepal to create a TTS application check it out