Here is a list of a few companies I have seen that offer discounts for employees:
GiftTree.com
Contact Name: Sarah Dunlap
Phone: 800-931-3620 ext 258
Email: sarah@gifttree.com
Web Address: www.gifttree.com
Discount: 10% - 15% off
Sprint
Web Address: www.evpdiscount.com
Discount: varies
Apple
Discount: I have seen 5% off for some employees.
AT&T
Web Address: http://www.wireless.att.com/businesscenter/
Discount: I have seen 15% off.
Enterprise
Discount: Corporate Class Rate
Verizon
Discount: up to 25% off
AAA
Discount: 2 months free when your purchase 12 months of service
Dell
Discount: I have seen 12% off
Barnes & Noble
Discount: 5%
American Airlines
Discount: 10%
Walt Disney World
Site: http://www.orlandovacation.com/discounts