CEntrilo is a client for the Ventrilo voice system, running on Windows CE and Windows Mobile 2002.
It just features the basic stuff like

– channel browsing / jumping
– setting / reading comments
– speaking with others
– setting server:port, username and password
– you can get mfcce400.dll below also
– voice recorder button as PushToTalk key if “trigger level” is set to ‘0’
– just click on the empty(!!) PTT textbox and press the key you want to be assigned as PTT key

The only restriction is that it just supports GSM 11025Hz for now…

other sample rates *should* work aswell, but have never been tested
Other codecs than GSM wont be supported – sorry for that.

320×240: PDA WIN32
640×480: PDA WIN32
mfcce400.dll: HERE

Source: see here