Here is a few links with detailed maps and aerial photos from around the GTA (Greater Tronto Area):

• City of Toronto maps - (Works best with IE, basic functionality is OK with Firefox)
• City of Vaughan interactive Maps - (Works best with IE, minimal functionality with Firefox)
• Town of RichmondHill map resources - (works well with IE and Firefox)
• City of Brampton maps -
• County of Simcoe Map server - for Barrie and area (works well with IE and Firefox)
• York Region interactive Atlas - (according to the website it works best with IE, but Firefox seems to work OK as well)
• Of course if all else fails, there is always Google Maps