The Visual Studio 2010 SP1 is available for download here (Web Installer). The service pack is also available as ISO image (1.49GB)

From the download site:

This download installs Visual Studio 2010 Service Pack 1 (SP1). This service pack release addresses issues that were found through a combination of customer and partner feedback, as well as internal testing. These service packs offer Visual Studio users improvements in responsiveness and stability, as well as completes some high-impact scenarios requested by customers. The full list of updates included in this service pack can be found here.