Are there free software that can open .ai file created in Adobe Illustrator?
A 5 second Google search found this candidate; http://aiviewer.com and this info; http://weblogs.asp.net/jongalloway/opening-adobe-illustrator-ai-files-when-you-don-t-have-adobe-illustrator
I've absolutely no experience with that software and that trick to simply rename .AI to .PDF can't be tested as I don't have AI.