A sailor patrols in a helicopter off Somalia, 17 September 2008
International navies are already escorting some Somali aid deliveries.
The European Union has agreed to establish an anti-piracy security operation off the coast of Somalia.
French Defence Minister Herve Morin said at least eight countries have agreed to take part.
The deal follows the seizure of a ship laden with 33 tanks - a $20m (£11m) ransom is wanted for its release.
Meanwhile, police in Kenya have arrested a maritime official who said that the battle tanks were destined for southern Sudan, rather than Kenya.
Andrew Mwangura - who's the spokesman for the Kenyan chapter of the Seafarers Assistance Programme - is likely to be charged with issuing an inflammatory statement.
A police official is reported to have said they want to question him about the allegation that the tanks on board the Ukrainian ship were going to South Sudan - a claim strongly denied by Kenyan and Ukrainian authorities.
But Western sources, who spoke on condition of anonymity, told the BBC that the tanks on board the ship were bound for the autonomous government of South Sudan, in possible contravention of a peace accord.
A British report says that Somali piracy has more than doubled this year, with more than 60 ships attacked so far and between $20m (£11.3m) and $30m (£16.9m) paid in ransom.
The French announcement was made after a meeting of EU defence ministers at Deauville, in northern France.
"There is very broad European willingness," said Mr Morin. "Many countries want to take part."
"We have (been) given a mandate to continue the planning for the launch of this operation in the month of November."
The announcement came as the International Maritime Bureau (IMB) reported a further three attempts to seize ships overnight.
"There are continuing attacks in the Gulf of Aden and off Somalia," said Captain Pottengal Mukundan of the IMB.
"It is a matter of great concern. We need more resources to deal with the problem."
According to the interim Somali government, the pirates holding the Ukrainian ship laden with tanks have begun negotiating with the ship's owners.
The Faina, which was carrying T-72 tanks, rifles and heavy weapons when it was seized last week, is being held off the coast, near the town of Hobyo.
The ship is surrounded by US warships, which is not allowing the heavy weapons to be taken off the ship.
A Russian frigate is approaching the area to join an international blockade, and is reported to have marines and special forces commandoes on board.
Piracy off the coast of Somalia has cost up to $30m (£17m) in ransoms so far this year, a report has said.
The study by UK think-tank Chatham House said the number of hijack bids had more than doubled to 61 in 2008.
The report said ransoms received were in the range of $500,000 (£283,000) to $2m (£1.1m) per ship and that the pirates were becoming more aggressive and assertive.