Here is a quote from The ADSL Forum:

"Copper telephone lines are everywhere. There are nearly 750 million now, and the next century will begin with a number closer to one billion. Today they connect telephones, fax machines, and computers at very slow speeds -- 28.8 kbps for modems, 128 kpbs for ISDN. Tomorrow, with ADSL, they will connect computers and televisions at speeds up to 9 megabits per second, 300 times faster than modems, 70 times faster than ISDN. ADSL will remove the last bottleneck to high speed access for the Internet, corporate LANs, video on demand, video education, and myriad applications we can only imagine today."

DSL comes in many flavors such as IDSL, HDSL, BDSL, ADSL, etc. The first letter denotes speed and method used but generally they are all in the same Digital Subscriber Line family. This is the way of the future for Internet access. It blows away ISDN and is priced in the range that every homeowner who uses the Internet can afford.