It depends on exactly where you are.
1. Cable Modem through your local cable company
2. High speed access through a satellite provider (Dish or Direct TV)
3. DSL through your phone company.
There are others as well.
Mark and Kari Shea
San Diego Real Estate Experts
Investment, Foreclosure & Short Sale Specialists,
Development Opportunities & Traditional Real Estate
PS Ask your agent for a list of service providers