Business Town - Marketing plans and other business topics.

Communitelligence.com - Knowledge-sharing portal aimed at improving organizational and interpersonal communication addressing key topics including public relations, internal communication, marketing, presentation skills, writing and business strategy.

KnowThis.com - Knowledge source for market research, marketing plans, internet marketing, marketing careers & much more.

Marketing Showroom - Collection of Web based marketing items that can help grow and market your business.

MPlans.com - Marketing plan software and sample marketing plans.