Nokia is buying Trolltech, the publicly traded Norwegian open source ISV, for roughly $153 million cash.

Gee, and Trolltech just joined the LiMo Foundation, the anti-Nokia/anti-Microsoft mobile consortium that's building a middleware-focused Linux handset platform that can be shared by its members with third-party access to the APIs, and not Google's flashier Linux-based Android effort.

The acquisition is practically in the bag.

Nokia is offering a 60% premium for the 250-man shop and 66.43% of the shares are already pledged to it. The Finnish cell phone giant, with its 40% market share, expects the deal to close next quarter.

It says the acquisition will "accelerate its cross-platform software strategy for mobile devices and desktop applications, and develop its Internet services business" - meaning the Nokia Ovi web portal that now figures a music store.

"With Trolltech," it added, "Nokia and third-party developers will be able to develop applications that work in the Internet, across Nokia's device portfolio and on PCs."

Nokia described its software strategy for devices as based on "cross-platform development environment, layers of software that run across operating systems, enabling the development of applications across the Nokia device range" and offered, as examples, web runtime, Flash, Java and Open C.

As a result it expects its S60 and Series 40 phones to get more competitive quicker - against Apple and Android, one assumes.

It's thought a Linux-based S60 would make a perfect foil for Android.

Nokia promised to "embrace" open source technology and "take further the open source development culture found in Trolltech."

It said it would continue to develop Trolltech's products, support new and existing customers, continue to license Trolltech widgetry under both commercial and GPL (soon to be GPLv3) licenses, and accelerate the commercial and open source adoption of Trolltech's Qt multi-platform GUI framework - the stuff that KDE, the Linux graphical interface, is based on.

In fact Nokia said it would apply to become a patron of KDE and pledged to honor the KDE Free Qt agreement.

Skype, Google Earth, Adobe Photoshop Elements, Lucasfilms and another 5,000 customers also use Qt but, just to confuse things, LiMo has specified GTK as its GUI toolkit so this is where everybody's strategy gets hazy.

Trolltech's established Qtopia application development platform for Linux devices like mobile phones, set-top boxes and portable media players is supposed to have shipped in some 10 million gadgets. This is probably what Nokia wants to ward off the threatening Android.

Of course Trolltech also has its own open source-based Greenphone, and it's tight with OpenMoko and its Linux/GTK-based Neo1973 phone.

To reassure the open source community, Nokia and Trolltech's founders Haavard Nord and Eirik Chambe-Eng put out an open letter saying that "Nokia and Trolltech employees will form a working group to identify ways of further improving our relationship with the open source community." They're looking for comments at opensource@trolltech.com.

Trolltech was started in 1994 and went public on the Oslo exchange in July of 2006.