Nature of Transfer
An eligible Service member may transfer up to the total months of unused Post-9/11 GI Bill benefits, or the entire 36 months if the member has used none (unless DoD/DHS limits the number of months an individual may transfer).
Family member use of transferred educational benefits is subject to the following:
Spouse:
May start to use the benefit immediately.
May use the benefit while the member remains in the Armed Forces or after separation from active duty.
Is not eligible for the monthly stipend or books and supplies stipend while the member is serving on active duty.
Can use the benefit for up to 15 years after the service members last separation from active duty.
Child:
May start to use the benefit only after the individual making the transfer has completed at least 10 years of service in the Armed Forces.
May use the benefit while the eligible individual remains in the Armed Forces or after separation from active duty.
May not use the benefit until he/she has attained a secondary school diploma (or equivalency certificate), or reached 18 years of age.
Is entitled to the monthly stipend and books and supplies stipend even though the eligible individual is on active duty.
Is not subject to the 15-year delimiting date, but may not use the benefit after reaching 26 years of age.
http://www.gibill.va.gov/gi_bill_info/ch33/transfer.htm
Transfer rights
The right to transfer Post-9/11 GI Bill benefits to a spouse or child is one of the most attractive parts of the new program to many career members.
In general, transfer rights are available to those with at least six years of service who agree to serve an additional four years in the military. Special rules apply to people who, on Aug. 1, 2009, were not able to serve an additional four years because of high-year tenure restrictions or because they already had an approved retirement date.
The service member allocates the amount of benefits to be shared, which must be done in writing. The transfer can be rescinded at any time and the amount of benefits being shared also can be changed, although changes are limited to one per month and the amount of shared benefits cannot exceed what members would have received if they did not share their GI Bill benefits.
http://www.armytimes.com/benefits/education/online_hbml10_education_post911gibill/