Pretty sure I have the solution...
In OL2002, a hyperlink to a network file will NOT display properly (blue underline) for the recipient of that email IF Word is being used as the email editor.
In OL2002, you can get the recipient to see the hyperlink to a network file IF Word IS NOT being used as the email editor.
what that said... OL2007 uses Word for both the rendering engine and the composition engine to provide a uniform experience.
(reference: http://support.microsoft.com/kb/933793 )
Since Word07 is being used as the default editor of OL07, it is safe to assume that hyperlinks will not carry over to OL02 (not sure about other versions).
OL07 uses Word07 as the email editor and it CANNOT be turned off.
If anyone else wants to add their 2cents I would love to hear it!