the only difference that i can discern between upsampling and oversampling is that oversampling is multiplication of the sampling frequency by an integer amount (i.e. x2) and upsampling by an non integer amount (i.e. x3.14159)

take a look here for more guff...

http://www.audioholics.com/techtips/specsformats/upsamplingvsoversampling1.php

cheers

julian