The UK is prohibited from making criminal records generally available to other governments under EU privacy laws. The UK can only pass on specific information where there is 'justifiable cause'. There's no fixed definition of 'justifiable cause' but it's likely that it is mainly interpreted as relating to 'cross-border' crimes, such as drug-smuggling, people-trafficking and child-sex tourism. It's extremely unlikely that the US authorities would know about a conviction for fraud (unless, of course, it related to something like fraudulently obtaining a passport).
Several AB contributors have posted here to state they've entered the USA, under the Visa Waiver Program, by simply 'forgetting' about their convictions.
If you applied for a visa, it's likely that you'd be refused. (It's hard to work out exactly what crimes result in the refusal of visa applications. As an example though, someone posted to state that their partner waited 6 months before being refused a visa because of 2 convictions for driving without insurance).
Chris