(New in Nov 2009) Crossbow is a scalable software pipeline for whole genome resequencing analysis. It combines Bowtie, an ultrafast and memory efficient short read aligner, and SoapSNP, an accurate genotyper, within Hadoop to distribute and accelerate the computation with many nodes. The pipeline can accurately analyze over 35x coverage of a human genome in one day on a 10-node local cluster, or in 3 hours for about $100 using a 40-node, 320-core cluster rented from Amazon's EC2 utility computing service.