If you have a capital loss in 2007, you can use it to reduce any capital gains you had in the year, to a balance of zero. If your capital losses are more than your capital gains, you may have a net capital loss for the year.
Generally, you can apply your net capital losses to taxable capital gains of the three preceding years and to taxable capital gains of future years.
for more information, see below http://www.cra-arc.gc.ca/tax/indivi...come/lines101-170/127/loss-deduct/menu-e.html