Congressional Budget Office Cost Estimate: H.R. 4709: Law Enforcement and Phone Privacy Protection Act of 2006 [open pdf - 13KB]
"CBO estimates that implementing H.R. 4709 would not have a significant cost to the federal government. Enacting the bill could affect direct spending and revenues, but CBO estimates that any such effects would not be significant. H.R. 4709 contains no intergovernmental or private-sector mandates as defined in the Unfunded Mandates Reform Act and would not affect the budgets of state, local, or tribal governments."
Congressional Budget Office: http://cbo.gov