I have a bunch of Eastings/Northings coordinates, using the UTM convention as far as I can tell - so basically, they are cartesian coordinates - that I would like to conver
The Proj.Net library is more likely to provide a simpler toolset for your needs.
You need to project from UTM (if it really is UTM - there A LOT of cartersian systems out there) to Geographic coordinate system. You will most likely need to find out the datum of your data as well. If you have have your data in a shapefile then look at the .prj file in a text editor - it will contain the projection information. Otherwise you need to go back to the data producer and ask them about the projection.