I answered your question here:
http://www.theanswerb...l/Question991070.html
To reiterate:
1. The USA does not recognise the UK's Rehabilitation of Offenders Act. Although your conviction is now spent for most UK purposes (including your application for a personal licence) it will NEVER be spent as far as the US authorities are concerned.
2. Theft is regarded by the US immigration service as an offence of 'moral turpitude'.
3. The US Immigration and Nationality Act states that anyone who has ever been convicted of an offence of moral turpitude is ineligible to enter the USA (unless they were only convicted of a single offence prior to their 18th birthday).
4. In consequence of the previous paragraph (and assuming that you weren't under 18 when you were convicted) the US Embassy MUST (in the first instance) REFUSE your visa application. (They have absolutely no discretion whatsoever. It's written into US law).
5. When your application is (initially) refused, it can then be referred to Washington as an application for a 'waiver of permanent ineligibility'. That process takes many months. While (for a single minor offence, several years ago) it's quite likely that you'll receive the 'waiver' (and hence your visa) it's probably already too late to get a visa for travel during this summer.
Chris