BridgeURL. A lot of people use various URL shorteners but I have always favored Bit.ly. Bit.ly has recently introduced Bit.ly Bundles which allows users to group several URL's together and then share one URL. There are several features that you can use that increase the use of Bit.ly Bundles.
With each site you can add a title, description and notes to the page, making the tool very useful to share several links in a presentation. You have the freedom of arranging your links in a particular order as well, which can also be a benefit for presenting websites. Once you share your bundle, people who view it can comment on the bundle, therefore your websites can start a conversation and can lead to a discussion on effectiveness and use of the websites.