I think that it's totally fine. It really depends on how high of a priority you place on the photography aspect of your wedding. Is your friend going to do formals or just candids? I'm sure since it's a friend he/she will want to do a great job for you, so go ahead and still be specific in telling him/her what types of shots you'd like to do. Make a very detailed list of the formal ones i.e. "Bride with Mom, Bride with Mom and Dad, Bride with flower girl, Bride with Ring Bearer...." Do that ahead of time so your friend can help you make sure you get every picture that you want and no body feels left out.
As far as printing goes I would recommend NOT going to Target or WalMart. My personal favorite is a place called Universal Color in New Hope. Their website is universalcolor.com. They are a chain but I don't know of another brick and mortar in MN. They have a GREAT online presence, you can upload photos to their site and get prints, photo books, gifts, and enlargements right there and have them shipped to you for really reasonable prices. They also have live Customer Service if you have questions. Always do Matte not Glossy--it looks way more professional.
Possible downsides-- depending on the experience of your friend, you may not get any artsy/creative shots, you're relying on that one person's equipment to work perfectly, not run out of batteries or card memory/film, and that nothing happens once the photos are taken. And as much as you trust and love your friend, accidents do happen. So make a back up plan!
You could get creative and have ALL of your guests be candid "photographers", especially at the reception-- either with disposables or ask them to up load there favorites from their own cameras on a certain photo site (you'd have to set that up ahead of time) with creative wording like "we don't want to miss a single moment of our wedding please help us treasure each memory by uploading and sharing your favorite photos that you took at our wedding" or something like that...
Hope that helps! I had a professional for my wedding and LOVED the photos, but I am a photographer on the side and have done quite a few friends weddings with much success, so I can really see both situations working wonderfully. Good Luck!