This excerpt taken from the NT 10-K filed Mar 2, 2009.
Employee stock purchase plans (ESPP)
Nortel has stock purchase plans for eligible employees to facilitate the acquisition of NNC common shares at a discount. The discount is such that the plans are considered compensatory under the fair value-based method. Nortels contribution to the ESPPs, as defined in note 20, is recorded as compensation expense on a quarterly basis as the obligation to contribute is incurred.