Originally Posted by
Buffeldrek
Due the changes in AC2007 a'desk had to make a new dwg fileformat (dwg2007)
AutoCAD 2005 works with the fileformat (dwg2004) - so you can't open a dwg2007 on an Autocad 2005 or lower. Therefore you will have to save as fileformat 2004 for other user to be able to open your drawing.
For other users to view - Autodesk's Trueview is the thing as already said.
But there is also AutoDesk TrueConvert - also a free programm you can give users (or third parties) where they can convert your 2007 dwg to a lower fileformat. So it all depends a bit on the situation where you are in.