There are a handful of islands in Casco Bay (the bay Portland sits on) which have yearround residents. The Casco Bay Lines will take you to these islands. See http://www.cascobaylines.com/ It's an inexpensvie way to get out on the water. Not a tour boat, you won't have a narrator. You could take a quick cruise over to Peaks Island (15 mins tops) or take one of the boats that goes farther down the bay. Of the islands you can explore on foot, I find Peaks and Cliff most interesting.

If I had visitors with just one day in Portland, I'd make sure to take them to the Portland Head LIght in nearby Cape Elizabeth, see http://www.portlandheadlight.com/

I'd also take them to the Old Port, paying special attention to Commercial, Fore, Market and Exchange Streets.

I love pretty architecture, so I'd give them a quick car trip through the western end of town; if you call up Portland on Mapquest, it's roughly that area betwen the Maine Medical Center and the Western Cemetary. Lots of beautiful old houses in that area.

Also, see http://www.portlandmaine.com/

Thanks MicheleS It sounds wonderful. Definetly will go to Portland Head light. Thanks