At the start of the Autodesk Inventor LT technology preview download process, you specify an email address. This email address is used to send you your serial number. You use the serial number as part of your activation process. Once activated, the technology preview will operate until May 1, 2008 - not 2007 as some believe. There has been some confusion on this issue. We may update the download page to make this more obvious.
The serial number and activation process are good for one computer. If you have multiple computers in your company and want a copy of the Autodesk Inventor LT technology preview on more than one computer, you will need a separate serial number for each computer. You cannot use a serial number more than once. We may also be more explicit about this on the download page.
So far the response has been almost overwhelming. Thanks to everyone who downloaded the technology preview and the feedback we have already received. Keep up the good work.