San Francisco--Flycast Communications Corp., San Francisco, said Thursday that it has signed a pact with yellow pages marketer R.H. Donnelley Corp., Purchase, N.Y., to provide access to the Flycast advertising network. The deal means R.H. Donnelley will offer Flycast's targeted Internet advertising services as part of its fledgling Internet marketing and e-commerce business, named "get digital smart." The deal fits both companies' business model. Flycast advertising, reaching 2,100 Internet lower-traffic niche publishers, is designed to provide cost-effective advertising with measurable return on investment. That's of greatest appeal to cost-conscious small and midsize businesses. R.H. Donnelley sales forces sell $1 billion in yellow pages advertising annually, and Internet advertising is a logical, if unproven, extension.