Listening to MP3s of robotic voices reading stories from the Web is a good way to prepare for the eventual downfall of mankind at the hands of our robotic overlords. If you're into that kind of thing, Hearwho will do all the heavy lifting for you by converting any text you feed it into a downloadable MP3 file.
If you've spent hours amusing yourself playing with AT&T's text-to-speech demo, you'll be glad to know that Hearwho does away with the somewhat annoying 300-character limit. I dumped an entire 800-word story into the text box and had a playable MP3 file in around 15 minutes.
To speed up the process, you can either use less text or dial down the quality. There are four compression settings to crunch a file down to a proper size. You can also toggle between male and female speakers, and whether you want it spoken in English or Spanish.
One thing to note is that if you're doing this with blog posts, the blog you're grabbing the feed from might already have an audio-RSS feed that you can simply subscribe to. A good directory of these feeds can be found at Stitcher, which also has a really neat iPhone Web app.
Note: Hearwho's servers are pretty slammed right now. Your text might take a half hour or longer to get converted--which is abnormal.