The only free voice dialing app that I know of (called Voice Dial) is basically a rip-off from the AT&T (GSM) version of the Palm Centro. I don't know that it is exactly free, but you can't buy it (that I know of). That being said, it is also the only Centro voice dialing app (as far as I know) that does true voice recognition. Other pay apps, such as VoiceDialIt, require you to pre-record your voice commands on the phone - annoying to say the least.

Anyway, the installation process for VoiceDial is a bit complicated, but it is described well in this thread (which also includes the files you need to download as attachments - you will have to register for a free account to download them):

VoiceDial with Centro on Sprint is Possible... - TreoCentral.com

Note: You will need a program called Resco Explorer (Resco Explorer 2009 for Palm OS) to make this work with the instructions from the thread (you use it to install the files into the phone's RAM and change the attributes on three of the files to "Launchable"). Although the initial post indicates that the 14-day free trial of Resco Explorer will not work, a later post indicates that it will. Resco Explorer, although a great program (and one that I have purchased), is a bit expensive at $29.95 just to get *free* voice dialing working . I suggest using the 14-day free trial version to get voice dialing working and buying Resco Explorer only if you think it is worth the $30 (I did).

One last thing to note - the Voice Dial app has two annoying things about it:

(1) You cannot use it with a bluetooth headset (although I have been told that a wired headset works with it).

(2) The voice prompts play only through the speakerphone and not through the earpiece.

Other than that, it works great on my Sprint Centro. I have it assigned to launch when I press the side button. Hope this helps.

-JP