I haven't followed Rebtel very closely, but they've been doing some pretty interesting stuff as they expand. I have watched DigiLinea for about a year now as they've continually expanded services in Latin America. They've been incredibly strong there.

This notice might be a sleeper that gets overlooked by a lot of the industry, but I'd say look for very strong presence and growth in VoIP services in Latin America from this alliance.

Rebtel Partners With DigiLinea on Mobile VoIP
Partnership Will Provide Enhanced VoIP Services for US & Latin America
DORAL, Fla., MILWAUKEE, and STOCKHOLM, Sweden, May 21 /PRNewswire/ -- DigiLinea, the leading Voice over IP (VoIP) infrastructure and service provider to the US Hispanic and Latin American markets, announced today a partnership with Rebtel, a leading provider of VoIP telephony to provide expanded mobile VoIP services for consumers in the United States and throughout Latin America.

Rebtel will leverage the DigiLinea platform to offer local Latin American telephone numbers, unlimited calling plans, and direct termination. Rebtel will leverage the DigiLinea platform to quickly and efficiently create customized internet-calling services that lower their customers' cost of communications to and from Latin America while increasing service-provider revenue and profit per line.
[Full press release]