You can obtain a call sign of your own choosing within reason. The FCC allows licensed amateurs to applly for a new call through the vanity licensing program; you can make an application either by mail or online. The ARRL outlines the procedure at: http://www.arrl.org/applying-for-a-vanity-call. Of course, the call you are asking for has to be available, and must be permitted for you license class, as listed below:
- Technician and General: 1 by 3 or 2 by 3
- Advanced: 2 by 2 plus 1 by 3 or 2 by 3
- Extra: 1 by 2 or 2 by 1 plus any of the above
Note that 1 by 1 call signs are reserved for special-event stations only.
For a more complete description of the vanity call sign program go to: http://www.arrl.org/vanity-call-signs