Useful Networks, a location-based services company, on Monday said its Sniff  friend-finder service with 150,000 users in Scandinavia is now available in the United States.

Sniff, available in Scandinavia for about five years, now allows friends in the United States on the Sprint Nextel mobile network to “sniff,” or find each other, via SMS on their cell phones.

But Denver-based Useful Networks faces a fairly steep uphill climb in the United States.

In the last few months analysts have dramatically scaled back their projections for location-aware buddy services, citing American's discomfort with making their location available, even to friends. (Can Location Based Service FindItself?)

Consumers in most demographic groups have stalking and other privacy concerns, eMarketer analyst John du Pre Gauntt said.

“But consumers really have nothing to worry about, because we make it impossible for anybody to be located without being aware of it, and the carriers are very diligent about making sure of that,” said Chris Glode, senior director of product management for Useful Networks.

Unlike many of its U.S. rivals, Sniff does not require a software download. Users register by sending a short code from a Sprint device. Once registered, friends are charged $0.25 per successful Sniff.

The carrier and Useful Networks split the revenue at 50-50.  

“A lot of our competitors have gone with creating downloads and a lot of consumers are unwilling to download anything to their phones, so we made it simple with SMS,” Mr. Glode said.

By charging per successful Sniff, Useful Networks avoids the monthly recurring service charge that the company believes is another barrier to consumer adoption.

Useful Networks got the Sniff technology from its acquisition of Swedish company LB Soft, which launched the service with Telia, a mobile carrier in Scandinavia.

Since the acquisition, Useful Networks, which itself was acquired by Liberty Media, launched the service on two other Scandinavian carriers. The service has since been introduced on four carriers in the United Kingdom --Vodafone, Orange, O2, and T-Mobile.

“Scandinavia was our proving ground and now we want to enable that same model of cross-carrier consumer adoption in the U.K and the U.S.’” Mr. Glode said.