Scores of dot-coms have sprung up in the last couple years with promises to deliver goods and services faster and less expensive than agriculture's traditional distribution network. The Internet will handle $120 billion in agribusiness transactions by 2005, Morgan Stanley Dean Witter Venture Partners claims. To date, there has been more talk than action. Farmers and ranchers are not buying off the Internet in great numbers, but they are likely to as they become more accustomed to the technology.