First of all QT = QuickTime. Qt is what you look for :-)
And what exactly is your problem?

no, i mean i need to use QT SDK to develop a windows services. So i need to install qtservice, right?
how to install this qtservice?

So, as you ask for how to install it, I think, you have not created windows services up to now? Otherwise, just create a windows services and use Qt internally, which is no problem.

In 2009, there were lab entries for a Qt Service Framework [labs.qt.nokia.com]

There is a QtSolution for developing services at gitorious. look at the following page [qt.nokia.com]

QtMobility also contains som eservice framework, but I don’t know what it does exactly…

no, i mean i not able to install qtservice.

i get this error when i compile qtservice’s example

error: cannot find -lQtSolutions_Service-2.6d

which example? Do you have the QtSolution for the service?
And installing the service != compiling sources.

So you have a compiler problem (or a linker problem).

are you buiilding debug?
did you add QtSolutions_Service to your sources?