Reliable, Effective, and Sustained Procurement of New Devices for Emergency Responders Act of 2008 or the RESPONDER Act of 2008 - Amends the Communications Act of 1934 to establish the First Responders Interoperable Device Availability Trust Fund. Requires that the Fund consist of 5% of the net proceeds from competitive bidding for broadcast licenses and 100% of the net proceeds from competitive bidding for D-block broadcast licenses. (Defines "D-block" as the electromagnetic spectrum between 758 and 763 megahertz and between 788 and 793 megahertz.) Requires that amounts from the Fund be used by the Administrator of the National Telecommunications and Information Administration to make grants, beginning in FY2012, to purchase interoperable devices for use by public safety personnel.
Entends the authority of the Federal Communications Commission (FCC) to grant a license or permit under competitive bidding provisions until September 30, 2014.