Looking for a phone that is mobile and will not cost you for your calls then try out the SI-680H IP SIP from Senao which is a 2.4GHZ Wireless Wireless LAN 802.11b VoIP Telephone
Its display is monochrome and is 64/128 encrypted for your security
The phone supports things like ftp, dns, telnet, udp, dhcp and tcp
The SI-680H can handle up to 14 different channels

Other Features Include

Phonebook that can store 100 name and numbers
Stand by time of 100+ hours and a talk time of around 3 hours.
Look back at your last 10 dialled missed and received calls
The ringer is high frequency and also has a viabrate function
You can also send an instant message
You can also hold, mute and transfer calls as well.