On my desktop computer I use Text Aloud with AT&T's Naturally Speaking Voices, which reads out web pages and/or any text that I highlight. I thought that was such a cool feature to have especially since the screen is so small. I've been searching for about two years now for a program that would allow this capability on my phone, but today I have NOT found such a application. However, I have found a really nice workaround, which involves two different programs.
The first and most important being the VOICE.
I'm using the Droid X, which has a wonderful built-in TTS program, but the voice sounds to robotic to me and sometimes a little hard to understand. So for this I found in the android market a voice called: LOQUENDO TTS SUSAN. I find this voice to be amazing but NOT CHEAP ($6.00), even better than the one on my desktop. I say this because it comes with additional features not found in my desktop software, like if I type this

and have the software read it, the program will give a very realistic laugh. If I type this

the program will return a realistic crying sound. If I type this xxx, the program will blow kisses. etc.
Now, the way I use this is with COPY AND PASTE, which is built-in to the web browser and gmail.
Once I copy the text to be read I paste it into a program called: LANGLEARNER SPEAKER, which is FREE in the market. Once the text is pasted into this program there is a "SPEAK" button at the bottom which reads the text aloud.
I realize at first glance this sounds like a lot work, but its really not with a little practice and I find myself using this a lot in my daily use of the phone and its also good practice in Multi Tasking Programs.
Also for additional voice, Google provides a program call: SVOX CLASSIC TTS.
For a great translation program that works with all these voices, I use: TALK TO ME.
Because of the small foot print and the amazing sound, I am REALLY enjoying my phone these days.
HOPE THIS HELPS.