Jack Phillips, the founder of Performance Resources Organization, a consulting firm specializing in accountability and ROI has put together a collection of tools on the ROI Institute website that might help you figure out the ROI of the training project.   The tools are at:

http://www.roiinstitute.net/tools/

An important step in calculating ROI is calculating costs to create Learning.  The cost of internal employees is a very important part of that cost.  When doing a project plan, I've found it helpful to calculate the hourly cost of the employee including bonuses, benefits, taxes, etc.   Here's a spreadsheet I have used.  Please test it and let me know if I made any mistakes in the comments and I'll fix them.  Also any recommendations for improvement are also appreciated.  

ASTD has released its 2008 State of the Industry Report online for ASTD members.  Here are my quick notes. 

I recently posted this question to the ASTD National group on Linked In: