The move follows the May decision by the authorities in Munich, the capital city of Bavaria, to equip all of the 14,000 computers in its public administration with Linux and other open-source office applications.
"We had an important meeting this month to discuss what we need to know if we make the switch to open source and will meet again on 14 October to plan pilot tests," said Markus Donsbach, IT director for the League of Cities in Rheinland Pfalz.
"Many of the cities have to make decisions by the end of this year because their contracts with Microsoft expire early next year."
The cities, Alzey, Kaiserslautern, Koblenz, Landau, Mainz, Neustadt, Speyer, Trier and Worms, are among the largest in the state.
Donsbach said most major German cities and many smaller ones are giving open-source software "serious thought", largely because of tight IT budgets.
The cost of licensing Microsoft products and the lack of support for some, including the NT operating system, which is still used widely in many city councils, are among the chief reasons for the growing interest in open-source products, he added.
One big hurdle for the cities to migrate to open-source software could be their wide use of customised software programs.
"The cities have systems running on different IT infrastructures," Donsbach said. "The task force that we've establish intends to contact all the vendors and find out if they already provide interfaces to open-source systems and if not, whether they plan to provide these in the near future."
Eager to maintain a position in Germany's huge public-sector market, Microsoft has been willing to bend on prices to keep key accounts for its Windows operating system and other products.
In April, the German Interior Ministry signed a licensing agreement with Microsoft to receive favourable conditions for both buying and leasing the US company's software products.
The deal came just weeks after Microsoft chief executive officer Steve Ballmer paid a visit to government officials in Germany.
John Blau writes for IDG News Service