The New York Times recently had an article in which they suggested some of the popular baby names from 2009 were influenced by Twilight.* (Thanks to bookshelves of doom and Fuse #8 for the links).
It's an interesting article, but as a bit of a name geek myself (I collected baby names books as a teenager and watched for the new Top 100 names list every year), I question whether the books really made that much of a difference when discussing the most popular names of 2009. As the spokesperson from the Social Security Administration points out in the article, Jacob has been the #1 most popular boy's name since 1999. Isabella, the most popular girl's name in 2009, has been hanging in the top ten since 2004, ever since it first made the top 1000 names in 1990.
The names that might have a little credence are Bella (#58) and Cullen (#485 for boys). Bella didn't make the top 100 in 2008. Cullen jumped in popularity the most of any boy's name - but we're still talking only 555 kids, or about 273 more than last year. And I'm surprised there's no mention of Emmett, which had a similar rise in popularity from #547 in 2008 to #332 last year.
If you're interested in names, definitely check out Social Security's popular baby names site. You can do all kinds of fun stuff tracking the popularity of names over the years (mine is about as unpopular as it's ever been, at least since these statistics were kept) and paging through really long lists of the 1000 most popular names in the U.S. And hey, maybe you'll notice other trends due to popular culture.
McKinley, Jesse. "A Name for Newborns Thanks to Vampires." The New York Times. May 7, 2010. Accessed from www.nytimes.com on May 15, 2010.