The Infrared Array Camera component of the Spitzer Space Telescope Extragalactic First Look Survey

We present Infrared Array Camera (IRAC) data and source catalogs from the Spitzer Space Telescope Extragalactic First Look Survey. The data were taken in four broad bands centered at nominal wavelengths of 3.6, 4.5, 5.8, and 8.0 mu m. A set of mosaics and catalogs have been produced that are approximate to 80% complete and approximate to 99% reliable to their chosen flux density limits. The main field survey covers 3.8 deg(2) and has flux density limits of 20, 25, 100, and 100 mu Jy at wavelengths of 3.6, 4.5, 5.8, and 8.0 mu m, respectively. The deeper "verification'' survey covers 0.25 deg(2) with limits of 10, 10, 30, and 30 mu Jy, respectively. We also include deep data in the ELAIS-N1 field, which covers 0.041 deg(2) with limits of 4, 3, 10, and 10 mu Jy, respectively, but with only two wavelength coverages at a given sky position. The final bandmerged catalogs contain 103,193 objects in the main field, 12,224 in the verification field, and 5239 in ELAIS-N1. Flux densities of high signal-to-noise objects are accurate to about 10%, and the residual systematic error in the absolute flux density scale is similar to 2% - 3%. We have successfully extracted sources at source densities as high as 100,000 deg(-2) in our deepest 3.6 and 4.5 mu m data. The mosaics and source catalogs will be made available through the Spitzer Science Center archive and the Infrared Science Archive.