Internet access is readily available and generally reliable. You can ask your landlord and/or letting agent for help. If you are in a house, the bill will be brought to you and you pay directly.
Serviced apartment buildings provide internet services and usually bill you directly. Costs range from $20-$40 a month, depending on the package you require (speed).
Many cafes across Hanoi offer free Wi Fi to patrons, so this is a good back-up option while your home connection is set up.