Iconfactory has released xScope 3.5 this week, with retina support for the Retina MacBook Pro and improved mirroring that allows a Photoshop document to be mirrored while being edited. The rulers can be inverted to make measuring on dark backgrounds easier, alignment marks can be displayed on the ruler, tools work in full-screen apps on Lion and Mountain Lion and more.
xScope is a US$29.99 purchase through the Mac App Store or direct download. You can try it before buying it by doing the direct download option.
