Skype is set to announce Wednesday a $29.95-a-year service offering unlimited calls to wireless and traditional landline phones. Or up until December 31st, 2007 if you sign up now at the promotional rate of $14.95. By doing so Skype hopes to mainstream phone services and challenge other VoIP providers that can cost you anywhere from $300-$400 per year.

Currently, Skype users had to prepay for credits to make such calls.

"Consumers like to pay on a subscription basis," says Don Albert, Skype's general manager for North America. "Now, our consumers have the option to do either one."

The good news, he says: "Either way you go, it's cheap."

This new offer is limited to residents in the USA and Canada, and the calls have to originate and terminate in those two countries.

Users can still make PC-to-PC calls free of charge and have the option to pay per call for PC-to-Phones. The charge is about 2.1 cents a minute in the two countries and higher elsewhere.

With things just starting to heat up for VoIP some predict by 2011 26 million U.S. households will use some sort of VoIP, up from 6.5 million today.

To help sweeten its new plan Skype is offering people who sign up by Jan. 31 will get a 50% discount on the annual fee, to $14.95. They'll also get about 100 minutes of free international calls and $50 in coupons for Skype gear, such as a Motorola headset.

Users who are already registered with Skype can subscribe to this deal at www.skype.com. Others will have to download the required Skype software and then sign up.