Give Olsen's Tree Service a call. They don't charge for doing estimates. I've used them in the past, as did several of my former neighbors, and we were all very happy with them. Very professional, very neat (good cleanup!) and competitive pricing. It wouldn't hurt to get some input even if you don't want to use a service to remove it.
As for an arborist, your best bet is to give the Bayard Cutting Arboretum (in Oakdale/Great River) a call. I'm sure they could put you in touch with someone reputable. Or you could just pop in and ask them. They've got a lovely little cafe there and the grounds are beautiful!
http://www.bayardcuttingarboretum.com