The library has a sizeable collection of materials by and about the Beatles as well as about John Lennon himself. Some of these items include The Cambridge Companion to the Beatles, Can't Buy Me Love: the Beatles, Britain, and America, The U.S. vs John Lennon (DVD), John Lennon: A Life, Power to the People (CD) and Lennon Remembers. Please check out the library's display for these and other items.
Also keep an eye out for the next issue of Rolling Stone. They'll be publishing what would end up being John Lennon's final interview. You can read more about the interview on Rolling Stone's website as well as delve into their exhaustive collection of information from Lennon's last days. You can read about Lennon's last day and a new documentary based on it at The Guardian's website. Other tributes include pictures and a short article from CNN, a collection of pictures of John and Yoko and The Beatles from Life, a nice blog entry at NPR about Lennon, and New York Daily News' article about Yoko Ono remembering his death. MSNBC has archival video of the day Lennon was killed and the LA Times has a photograph of the front page from December 8th, 1980. The Guardian also has a nice article about fans in the US remembering Lennon.