According to Tomshardware, Microsoft have now officially finished work on SP2 and have released it to manufacturing. Depending on language, the SP will be available in the coming months sometime.
Some things you might not know:
-SP2 will require an additional 495 MB disk space above your existing SP1 installation.
-There are a total of 172 patches in the SP.
-Microsoft expects more than 100 million PCs to be equipped with the SP within the next two months.
-The first available version will be in English.
-The download is around 260 MB.
IBM and Hewlett-Packard don't seem convinced about the SP. They are advising their employees not to install it pending further testing, for possible compatibility problems with existing software. Go here for a complete list of features.