As the others have stated, you cannot post a for sale by owner on trulia.com. If you want to get some web exposure, you should post it on zillow.com. You might also try craigslist.com. Milwaukee's craigslist community is very active.
Worth a shot. If you do not get a good response and are in a position where you need to sell more quickly, it will be worth your time to contact a local realtor.