Reconnecting Homeless Youth Act of 2008 - (Sec. 3) Amends the Runaway and Homeless Youth Act to revise requirements for services provided under grants from the Secretary of Health and Human Services for centers for runaway and homeless youth and their families. Limits the length of stay in such a center to 21 days.

Increases grant minimum allotments from $100,000 to $200,000 for states and from $45,000 to $70,000 for the U.S. Virgin Islands, Guam, American Samoa, and the Commonwealth of the Northern Mariana Islands.

Prohibits the allotted amounts for a state for FY2009-FY2010 from being less than the allotted amount for FY2008.

Requires the plan proposed by grant applicants for a runaway and homeless youth center to include an adequate emergency preparedness and management plan.

(Sec. 4) Revises requirements for transitional living programs. Specifies that shelter and services may be provided by grant, agreement, or contract (currently, directly or indirectly) to homeless youth.

Increases the maximum length of continuous stay in such programs from 540 days to 635 days, if a youth would benefit to an usual extent from additional time in the program.

Requires a transitional living program also to develop an adequate emergency preparedness and management plan.

(Sec. 5) Requires the Secretary to give priority (currently, special consideration) to grant applicants for specified research, evaluation, demonstration, and service projects regarding runaway youth and homeless youth.

Requires the Secretary to give special consideration to proposed projects relating to: (1) behavior (currently, mental) health care for runaway and homeless youth; (2) access to educational and workforce programs to achieve outcomes such as decreasing secondary school dropout rates, increasing rates of attaining a secondary school diploma (or equivalent), or increasing placement and retention in postsecondary education or advanced workforce training programs; and (3) programs, including innovative programs, that assist youth in obtaining and maintaining safe and stable housing (which may include programs with supportive services that continue after the youth completes the remainder of the programs).

Requires the Secretary to ensure that selected grant applicants: (1) represent diverse U.S. geographic regions; and (2) carry out projects that serve diverse populations of runaway or homeless youth.

(Sec. 6) Requires the Secretary to report periodically to specified congressional committees and the public: (1) estimates of the incidence and prevalence of runaway and homeless individuals between 13 to 26 years of age; and (2) an assessment of such individual's characteristics.

(Sec. 7) Requires the Secretary to give priority to public and, as under current law, nonprofit private agencies for sexual abuse prevention programs.

(Sec. 8) Requires the Secretary to establish performance standards for grant recipients.

(Sec. 9) Directs the Comptroller General to study and report to specified congressional committees on the processes for making grants under the Runaway and Homeless Youth Act.

(Sec. 10) Redefines "homeless youth" to cover an individual seeking shelter in a runaway and homeless center who is less than a maximum age higher than 18, if the center is located in a state or locality with a child or youth-serving-facility licensure law or regulation that permits a higher maximum age.

Allows a homeless youth to participate in a transitional living program up to age 22, as of the expiration of the maximum stay permitted, if the individual commences such stay before attaining age 22.

Defines "runaway youth" as an individual under age 18 who absents himself or herself from home or place of legal residence without the permission of parents or legal guardians.

(Sec. 13) Authorizes appropriations for FY2009-FY2013.
Output: A bill to amend the Runaway and Homeless Youth Act to authorize appropriations, and for other purposes.