Go to http://mpucoder.kewlhair.com/Derrow/index.html
There are two articles over there:
"Split a DVD to 2 DVD-R's using Smartripper stream modus"
"Split a DVD to 2 DVD-R's using IfoEdit 0.89"
And, you know, both Smartstripper (or DVD Decrypter) and IfoEdit
are freeware.