A bit off-topic for this newsgroup...
Not sure about previous versions, but in MapPoint 2006, yes...
well, sort of. If I enter a starting point of Sacramento, CA,
and an ending point of Salt Lake City, UT, and click on Get
Directions, the following data is included in the route information:
Mile Instruction
---- -----------
0 Depart Sacramento
118.4 Entering Nevada
528.9 Entering Utah
650.2 Arrive Salt Lake City
You would need to manually calculate the mileage in each state
from the data provided (California 118.4, Nevada 410.5, Utah
121.3).