Vopium is a carrier-grade mobile telephony service designed to offer affordable and reliable international calls from any mobile handset. By using the Vopium application on mobile to make calls from home country, consumers and businesses alike can save up to 90% on international mobile and land-line calls. Unlike more restrictive mobile VoIP solutions, Vopium supports hundreds of handsets across Java, Symbian, RIM, Windows Mobile, iPhone and Android. Vopium was awarded the Frost & Sullivan Technology Innovation Award. Vopium is listed on NYSE Euronext (MVLOP).
Vopium has recently updated their device list and announced that it compatible with more than 1000 latest devices, Some newly added devices and upcoming devices are:

Vopium is Available for:

HTC Tattoo
HTC Pure
Nokia 5800 Navigation Edition
Nokia 6350
Nokia 6750 Mural
Sony Ericsson T715
Sony Ericsson C901 Green Heart
Sony Ericsson Naite
Sony Ericsson Satio
O2 XDA Serra

Coming Soon:

Nokia X6
Samsung SGH I5700 Galaxy Spica
Samsung SGH B7620 Giorgi Armani
Samsung W880 AMOLED 12M
HTC HD2
Blackberry Bold 9700