For more than two decades, U.S. Amateur operators have been "systematically" issued station call signs by the Federal Communications Commission as part of the initial licensing process. Until May 31, 1996, radioamateurs were not allowed to choose their station call signs.
New amateurs may get on the air once their license has been granted and their call sign has been assigned. FCC regulations now authorize operation on the basis of the license data appearing in their amateur service licensee data base. First-time licensees no longer have to wait until they receive the actual license document. Actually a paper document is not really needed. It is what is in the FCC database that counts.
The initial call sign a new amateur receives is determined by the license class the applicant qualifies for by examination. Most new radioamateurs begin their ham radio career at the Technician Class and are issued 2x3 format call signs since the 1x3 "N" prefixed call signs have all been assigned.
As a general rule, new call signs are available about two weeks after testing ...although they could be available in 2 to 3 days depending upon how fast the test session paperwork is sent to - and processed by - the VEC.
An easy way to find out your new call signs from the Internet is to access one of the online databases on the World Wide Web. A particularly good one is the call sign lookup operated Fred Lloyd (AA7BQ Scottsdale, AZ) of QRZ.com. Their database is updated very early every morning directly from the FCC.
A list of new call signs and licenses issued daily by the FCC are posted to the QRZ website. These lists are archived so that you can check to see if a call sign has been issued over a period of the past few days ...or weeks.