The Atlas of Canada has an interactive map of the historical treaties signed in Canada. If you click on an area with the information button, there is a link in the popup that will take you to the text of the original treaties.
http://atlas.nrcan.gc.ca/site/english/maps/historical/indiantreaties
Update, 2013: That link no longer works. You can find other maps here:
http://geogratis.gc.ca/api/en/nrcan-rncan/ess-sst/7ac840d4-638c-575e-9b77-e44c02b5dbdc.html
http://geogratis.gc.ca/api/en/nrcan-rncan/ess-sst/fe5cf14e-5081-5c43-9822-a6da6ef5d326.html
http://geogratis.gc.ca/api/en/nrcan-rncan/ess-sst/cb216b8f-8893-11e0-8ed0-6cf049291510.html