Data.gov was launched today as a catalog of Federal government data, but critics are griping that only 47 data sets (and 'non-controversial' ones at that) are included so far. The USGS provided 22 of them with others from a couple dozen other agencies.
Data.gov is intended to act as a central repository for federal government data, including XML, CSV, and KML files. There are raw data files and a few software tools or widgets provided. The site invites users "to actively participate in shaping the future of Data.gov by suggesting additional datasets and site enhancements to provide seamless access and use of your Federal data."