AdoreSoftphone for windows mobile 6.0/6.1 can be customized with your company logo.
Features
Customized with company logo/name SIP protocol support Codecs supported: g711,GSM Call timer Display Credit Time Display Balance Local signaling (Dial tone, busy, ring back, etc.) Redial Touch Tone Uses NEW RFC 3261 compliant stack
System Requirements:
OS Supported : Windows Mobile 6.0/6.1 CPU : 200 MHz ARM-type CPU, Memory: 64MB Memory Space : 1000 KB Audio : speaker & mic Internet Connectivity: Wi-Fi/GPRS/EDGE
If you have any queries, please let me know. I would be happy to assist you.