That's right! There is new stuff in .NET 2.0 SP1 libraries and you should know about changes in red bits because there will be MethodMissingException exceptions if you deploy solution developed with VS 2008 with .NET 2.0 as target framework and deploy it on machine with .NET 2.0 (without SP1).
Scott Hanselman created a nice compilation with changes.
Note: this do not affect existing solutions at all because of .NET framework compatibility policy
unless you've taken an advantage of fixed bug. In this case you should test
affected components (UPDATED in order to include valueable comments from Daniel
blog posts on the subject: