IVT, a startup that’s been quietly accumulating an impressive list of customers for the last three years, is launching itself to the public tomorrow as a service for corporate video. The company describes itself as a “YouTube for business,” something that was simply a nice analogy until recently, when Google launched exactly that product.

IVT’s service is a bit more comprehensive, however, most importantly in that it offers webcasting, which Google does not. It also converts all sorts of multimedia files into web-viewable Flash, including WebEx meetings, Polycom conference calls and slide decks. Customers include Cisco (c CSCO), AT&T (c T), IBM, Ernst & Young, Oracle, NEC, Rohm & Haas and EDS.

What’s great about the IVT platform is that most of it’s accessible from the web, but at the same time it hardly looks simple or easy to use, especially with different proprietary tools for publishing, webcasting and permission-based content viewing.

IVT’s newest product, called PrimeTime, is a branded internal video site created custom for each customer that organizes all the different videos and presentations for disseminating within a company. Employees can view, rate and post content directly, with permissions controlled by a manager.

IVT is still quite small, with 20 employees in northern and southern California. It has raised $3 million from Monitor Ventures and Tudor Investments. Besides Google, competitors include Kontiki, Cisco, Thomson, Wistia and Veodia.

Note: We received differing accounts of now much IVT has raised; $3 million is the correct amount.