For a flat fee, hoteliers would be able to use ancillary services’ content already loaded into Travelscream’s Social Media Toolkit dashboard or they can upload unpublished or additional offers targeted to particular guests or groups.

Travelscream co-founder and CEO Tom Griffin says hotel guests will receive a link to the iPhone app — which will be coming to Blackberry and Android devices, too — in their confirmation e-mails and the hotels get notified when a customer downloads the app.

Hotels can then offer consumers ancillary services on mobile devices before and durings their stays, and might even promote room specials after guests have completed their stays.

Griffin likens the Travelscream smartphone app to an opaque channel because hotels can offer guests unpublished inventory.

The app isn’t available yet to the public, but here’s a demo website.

This article is the first press mention of the app, and Travelscream officials plan to make an official announcement about it at Travelcom 2010 in Dallas next week.

Travelscream is offering licensing agreements with hotels at an introductory — but renewable rate — of $1,000 per year.

The licensing agreements involve no revenue share, Griffin says, adding “we didn’t want to get into the revenue share business.” Hotels keep all of the incremental revenue they earn through the app.

Developed by a third-party software company, the app is unique in the ancillary revenue opportunities it offers to the lodging industry, Griffin says.

Griffin says Travelscream has verbal commitments from several major U.S. hotel chains to participate in the service.