Arson is suspected in an early morning house fire today on Milwaukee’s north side.   The Milwaukee Fire Department was called to a fire in a boarded up 2-story home at N 26^th Street and W Port Sunlight Way.  The call came in at 2:30, firefighters were on scene within two minutes and the fire was extinguished in 10 minutes.   MFD officials say the fire was localized to the exterior of the south side of the building.  The two-story wood framed house is vacant and no one was found inside the structure.  Damage is estimated at $50,000 to the structure.   No one was injured while fighting the fire.