TeXShop is not available for Windows but there are some alternatives that runs on Windows with similar functionality. The best Windows alternative is TeXstudio, which is both free and Open Source. If that doesn't suit you, our users have ranked nine alternatives to TeXShop and five of them are available for Windows so hopefully you can find a suitable replacement. Other interesting Windows alternatives to TeXShop are Texmaker (Free, Open Source), TexitEasy (Free, Open Source), Bakoma Tex (Paid) and Inlage (Paid).
TeXstudio is an integrated environment for writing LaTeX documents. Our goal is to make writing LaTeX as easy and comfortable as possible. Therefore TeXstudio has numerous features like syntax-highlighting, integrated viewer, reference checking and various assistants.
TeXstudio vs TeXShop opinions
pros, cons and recent comments
Studio has project/session files, saves state of your work. TeX-sync works seamlessly in studio (did not test it for texshop)
Inlage (Intelligent LaTex Generator) is a shareware LaTeX Integrated development environment that allows the user input LaTeX by using Windows 7's Math Input Panel. The shareware version does not allow saving or compiling after 5 minutes of testing.