Subscribers to VoIP services grew 18 percent to 8.2 million users in the third quarter. However the overall growth rate slowed for a second straight quarter this year, according to TeleGeography research firm.

VoIP revenues are up two and a half times to $732 million across the U.S., compared to a year-ago level of $298 million.

Vonage remains the largest provider of VoIP with 1.95 million subscribers, followed by Time Warner, ComCast, and Cablevision.

Predictions have the market growth projected at 1.5 million new subscriptions in the fourth quarter to round out the year with 9.7 million or nearly 8.7 percent of all U.S. households. Revenues for 2005 are expected around $2.6 billion for this year, which is up from 2005's total of just over $1 billion.