USCIS started accepting H-1B petitions subject to the fiscal year (FY) 2012 cap on April 1, 2011. Cases will be considered accepted on the date USCIS receives a properly filed petition for which the correct fee has been submitted; not the date that the petition is postmarked.
The H-1B visa is a temporary worker’s visa for specialty occupations. The H visa is job and site specific; once approved, the employee is eligible to work at the job for which that visa was approved and ONLY that job.
The regulations define a “specialty occupation” as requiring theoretical and practical application of a body of highly specialized knowledge in a field of human endeavor including but not limited to architecture, engineering, mathematics, sciences, biotechnology, medicine and health, education, law, accounting and theology, and requires the attainment of a bachelor’s degree or equivalent.  Additional information regarding the requirements for an H-1B  visa, can be found here.
Each year, USCIS sets a specific numerical limit on the number of H-1B petitions accepted.  The current annual cap is 65,000, however, not all nonimmigrant petitioners are subject to this cap.   Some exemptions are made due to various reasons.   Some examples are:

  • Petitioners from Chile or Singapore as per U.S. Free Trade Agreements; and
  • An employer that  can demonstrate that it meets certain criteria related to or affiliated with certain institutions of higher education, nonprofit entities, nonprofit research organizations or governmental research organizations

In addition, 20,000 are made available under the Master’s Exemption. This requires foreign nationals to obtain a Master’s degree through an accredited U.S. institution of higher learning.
A chart including an up to date number of cap eligible petitions can be found here.
 
Page Summary: The H-1B Visa Cap Season for FY2012  began on 4/1/11.