There is a great new media player for Pocket PC, called Betaplayer, for both video and music. I don't think it supports Speex yet, but the developer says he plans to add that.
Take a lot at it--go to
www.corecodec.com, and follow the links to Betaplayer, look at its forum, where the development is discussed. The author (Picard) is quite open to suggestions, etc.
Anyone with a Pocket PC interested in media should take a look at this program.
The latest "stable" version is 0.4. (unless a new one came out today, I haven't checked.) The author also has several newer beta versions he calls "unstable". (Don't let the name scare you. They are not unstable, just not a full new version yet. As of version 7/25 WMA and WMV support was added. As of 7/28 Matroska, and support for the WMA voice codec.
Why I mention the latter, unless you hate Microsoft too much to use any of their formats, I have found WMA 9 voice to be a great codec for spoken voice. I encoded an audio book that I have on CD with it. This audio book was on 10 CDs, about 700 minutes of audio. I first tried the lowest setting with WMA9, at 4kbps, and found it unacceptable. But when I went up to the second lowest setting, at 5kbps, I found the results quite acceptable for spoken voice. Using that I fit the ten CD audio book into about 30 MB. If you have WMA9 on your PC, the voice codec is there, although not all encoders recognize it. Windows Media Encoder does, but I used DBPoweramp (you have to download and install their WMA pack from their Codec Central).
I can play them on my PPC in WMP, but now (as of version 7/28) I can also play them with Betaplayer. I also have a couple dedicated digital audio player devices that can play WMAs, but none of them I have will play these with the voice codec, or due to the very low bit rate.
Some people on the Betaplayer forum said that their PPCs will not play WMA voice (either with WMP or the new Betaplayer), although they have WM2003, which I also have. It might be that some builds of WM2003 will play it, others will not. I have an IPAQ 2210, still using the OS that came on it, the voice WMA files work fine. Try a short excerpt on yours before encoding a whole book.