Presumptive question, but I have to ask. Are you talking about changing three ‘Novell’ servers to “Windows 2003”?
That is a bit more than just ‘migration’!
There are several hundred thousand ‘hits’ on a simple google search ‘NDS to AD’.
In addition to migration this the opportunity to reorganize your structure, BUT less than 60 days may rule that out.
Good luck, we stand ready to help once the questions are clear.