I stumbled across a nifty scent database today which not only includes colognes, but aftershaves, soaps, essential oils, inscence, candles, candies or whatever. Of course it is limited by items this retailer stocks, but I still found this to be quite heplful.
http://www.smallflower.com/shop_by_scent.cfm
http://www.smallflower.com/shop_by_scent.cfm