There are a variety of ways you can easily transfer your project file from your Mac to your Windows computer. Firstly, to access any project you can open the Projects window in EverWeb and click the little arrow besides the project you want to transfer and select 'Show On Disk'.
If your project file is not in the EverWeb Projects window, you can locate it on your hard drive.
Then you can copy that project file to a USB drive, or even using a free service such as Dropbox.
If you transfer your project file from Mac to Windows, the project will actually turn into a directory when viewed on Windows. You will find an actual project file ending in EverWeb Project File.ewwinproj. You can double click this file to open it in EverWeb.
You can also drag the entire project directory onto the Projects Window in EverWeb for Windows. That will add the project to your Projects list.