Here is some definitions of learning organizations quoted from internet and books:

A Learning Company is an organization that facilitates the learning of all its members and continually transforms itself. (M. Pedler, J. Burgoyne and Tom Boydell, 1991 on http://www.skyrme.com/resource/kmres2.htm#Pedler)

Organizations where people continually expand their capacity to create the results they truly desire, where new and expansive patterns of thinking are nurtured, where collective aspiration is set free, and where people are continually learning to learn together” (Peter Senge, 1990 at http://www.skyrme.com/resource/kmres2.htm#Senge)

Learning organizations are those that have in place systems, mechanisms and processes, that are used to continually enhance their capabilities and those who work with it or for it, to achieve sustainable objectives – for themselves and the communities in which they participate. (at http://www.skyrme.com/insights/3lrnorg.htm)

“…….. defines organizational learning as the process of “detection and correction of errors.” In his view organizations learn through individuals acting as agents for them: “The individuals’ learning activities, in turn, are facilitated or inhibited by an ecological system of factors that may be called an organizational learning system” (Argyris (1977) p. 117).

The Learning Company is a vision of what might be possible. It is not brought about simply by training individuals; it can only happen as a result of learning at the whole organization level. A Learning Company is an organization that facilitates the learning of all its members and continuously transforms itself”.

Learning organizations are characterized by total employee involvement in a process of collaboratively conducted, collectively accountable change directed towards shared values or principles. (Watkins and Marsick 1992: 118)

References:
Senge, Peter (1987), The Fifth Discipline Fieldbook, (Batam: Inter Aksara)
Guns, Bob et. al. (1996), The Faster Learning Organization, (London: Pfeiffer & Company);
Agryris, Chris (1993), Knowledge for Action: A Guide to Overcoming Barriers to Organizational Changes, (California: Jossey Bas Inc.)