For a interesting and very technical introduction to CIGS (copper indium gallium selenium) technology, check out the 3rd quarter 2009 edition of Photovoltaics International Magazine – page 112. This article by ZSW is a good primer to get you up to speed with this thin-film technology. (This blows the Wikipedia "CIGS solar" description out of the water!)
The article is a good read for those of you looking into CIGS technology because it goes well beyond the overview of what CIGS is with discussion of chemical and structural analysis of thin-film cells.