Website

GIS-T is an interesting field. This just an Illinois data portal, but with a little searching you can find the same for any state.

From my hometown Urbana, vector and raster data for all the world!

"Access Illinois GIS data sets and documentation (metadata) for ArcIMS Interactive Map Services, USGS digital topographic maps, aerial photography, orthoimagery, orthophotography, geology, land use, natural resources, and infrastructure. Illinois data sets and map data layers are available for download free of charge."

GIS desktop service "designed for capturing, storing, handling, analyzing and deploying any kind of referenced geographic information in order to solve complex management and planning problems."

A platform for geospatial data.

I do not know these guys and gals personally but they seem the crowd that you want to have over for drinks.

The good guys:

"The Open Source Geospatial Foundation, or OSGeo, is a not-for-profit organization whose mission is to support and promote the collaborative development of open geospatial technologies and data."

A collection of tools and links to open source geo-stuff. Comes with helpful descriptions. *Beware of some faulty or broken links. If you encounter this problem, usually "google"-ing the link will bring you to the correct site.*