Glogster is a fusion between a blog and an electronic poster. It allows educators to create a virtual poster about any given subject. So in terms of library uses, think about upcoming events, special reading programs, or guest speakers/authors, etc. This recommended application was highlighted by The eLearning Site and is offered as a free trial version tool with optional upgrades ($0.50/year and $39/year).
Here are four links to help you learn more;
1) Registration & download information
2) Tutorial: Basic features & uses of Glogster
3) Glogster in 90 seconds
4) Glogpedia: Library of the best glogs created