My friend Rick Roberge has an excellent blog that covers all elements of selling with a concentration on using 21st century techniques like social media and inbound marketing.
All-in-one internet marketing software provider HubSpot blogs several times per day on all things inbound marketing and social media - highly recommended.
John Jantsch provides common-sense marketing advice and how-to articles for SMB companies.
Jill Konrath's fresh sales strategies blog provides ideas and insights on best practices for selling in today's difficult economic environment.
Excellent sales advice from the #1 cloud-based CRM platform provider.