1 Gbit = 128 megabytes
Keep in mind that internet connections are typically metered in Mbps or Gbps rather than megabytes or gigabytes per second. For example, Shaw's High Speed Extreme internet access is marketed as 15 Mbps, but in terms of megabytes this is actually 1.875 megabytes per second maximum as there 1 megabit = 0.125 megabytes.
http://en.wikipedia.org/wiki/Data_rate_units has more conversion factors