You can download it at http://www.prestosoft.com/download/ed18_setup.exe (EXE with installation -- 520 KB), at http://www.prestosoft.com/download/ed18_setup.zip (ZIP with installation -- 502 KB) or at http://www.prestosoft.com/download/ed18.zip (ZIP without installation -- 276 KB).
Here's what's new in 1.8:
- New feature: Autopick feature in Compare dialog that remembers matching file pairs
- New feature: View/Edit command accessible via the context menu
- New feature: Separate Copy and Copy With Padding Lines commands
- New feature: Windows Vista support
- Improvement: Improved current difference marker