The threat of a catastrophic split in Formula One appears much less likely following the decision of five rebel teams to enter the 2008 championship.
F1 appears set to avoid a damaging split in 2008
The move comes five days after F1's governing body, the FIA, set a deadline of 31 March for teams to enter for '08.
Renault, BMW, Mercedes, Toyota and Honda had all threatened to launch a breakaway series because they are unhappy with the way F1 is being run.
The five rebels said they "remained committed to improving the sport".
They have been pushing for more say in the running of the sport, a greater share of its revenues, and more transparency in its governance.
The GPMA statement said: "The teams look forward to beginning discussions with the FIA in order to finalise the regulations for 2008.
"The GPMA members are united and remain committed to improve the sport for the benefit of all stakeholders."
It added that "significant progress" had been made in "ongoing" discussions with F1 commercial rights holder Bernie Ecclestone.
A GPMA spokesman said the announcement did not entirely remove the threat of the teams going it alone.
"There are several open issues still to be discussed and it is too early to speak of a final agreement," he said.
But the move does dramatically reduce the threat.
Ecclestone (left) and Mosley are in talks with the GPMA
The GPMA is likely to have decided that it is better to sign up and try to effect the changes it wants from the inside than be isolated from discussions on the future of F1.
They will have been encouraged in this view by FIA president Max Mosley's statement in a letter to the teams last week that "although the 2008 sporting regulations are now fixed, any element could be changed on proposal of a simple majority of the entered teams".
The manufacturers are opposed to many of Mosley's plans to reduce the influence of technology in the sport.
The FIA announced on Monday that it had agreed with Ferrari, Renault and Cosworth a proposal that engine specifications should be frozen from 2008-12 - two more years than was voted into the 2008 rules last week.
An FIA statement said the plan was intended to "encourage research into engine efficiency and the more effective use of available energy".
It added that modifications to specific areas of engines would be permitted each year, but that these would not be allowed to improve performance.