The first ambulance services are launching bids to become foundation trusts within a year.
London Ambulance Service trust has become the first to start consulting on the change and North East Ambulance Service trust is expected to begin consulting soon.
The North West and West Midlands services are also hoping to become foundation trusts before April 2010.
However, some services face major challenges in meeting tough response time targets and may struggle to sign up enough members because of their huge areas and lack of traditional ties to the community.
On both counts, it is unclear what Monitor's standards will be, but the regulator is planning to judge trusts on three response time targets - which several trusts are not meeting - and one clinical measure.
The trusts are asking Monitor, which is consulting on changes to the compliance framework, to drop the target for category B (non-life threatening) calls.
North East Ambulance Service trust chief executive Simon Featherstone told HSJ the government's direction of travel for urgent care strategy proposed, at some stage, replacing the category B target with clinical indicators.
"We are saying that might be a better way of monitoring ambulance compliance [for Monitor]," he said.
A study for the London trust, which is not meeting all the targets, claimed that to meet response targets it would need at least 428 more staff.
It is in discussions with NHS London to secure extra funding, said trust chair Sigurd Reinton.
He said: "For ambulance trusts, to a degree there is such a direct link between performance and funding.
"We are optimistic we will come to an agreement [with NHS London]. They are sympathetic and want us to become a foundation trust."
Ambulance trusts are looking at ways of recruiting members through partnerships with other NHS providers and other organisations.
The London Ambulance Service is working with Age Concern London, the British Heart Foundation, Diabetes UK, Mind and the Stroke Association.
Mr Reinton said: "I am quite confident we will have very little difficulty in getting together a very large membership."
Ambulance Service Network director Liz Kendall said all ambulance trusts that had not begun the foundation trust diagnostic process with their strategic health authority planned to do so this year.
"They are all absolutely determined to get foundation trust status and I think ambulance services are particularly enthusiastic about the opportunity it offers in terms of engaging patients, the public and staff.
"They are looking at innovative ways of building those links."