Sometimes, it helps to see case studies of how others are doing things. For some reason today, I've come across several articles and blog posts that point you to some examples of how organizations have used social media as a communications strategy. Take a look!
"10 Social Media Campaigns that Rock! Learn How to do the Same!" ThoughtPick blog (June 8, 2009)
"iPhone Apps Put Brands in Hands," list of the successful brands and apps that best fulfill the promise of utility -- as well as some prominent missed opportunities, by Brian Morrissey (Nov 30, 2009)
"Twitter Success Stories," report details how 11 innovative businesses and associations use Twitter to improve their marketing and business objectives. (2009) [PDF]
"26 Social Media Marketing Examples in Detail," by Lisa Braziel (September 09, 2008; dated but useful)