From a press release by Autodesk today about Autodesk Inventor.

Autodesk Inventor PLE will be available from Authorized Autodesk Resellers beginning October 2006. To find your local Authorized Autodesk Reseller please visit www.autodesk.com/resellers

Engineering professionals and students will be granted a license for 180 days to use the software and sharpen their skills on personal projects before the license times out. During that time, users will have access to all functionality in the core Autodesk Inventor product that ships with Autodesk® Inventor(TM) Series software. Included free of charge on the Inventor PLE DVD, is the Autodesk Official Training Courseware title Introduction to 3D Design, which usually sells for US$47.99. Please note that Inventor PLE users will not have access to specialized Autodesk® Inventor(TM) Professional functionality, or the Autodesk® Vault or AutoCAD® Mechanical software applications.

Update 11-03-06: This is currently only available for the US.