KavaServices can add commands to the Services menu that let you:

• Translate text back and forth between 58 languages
• Move and copy files to particular folders
• Search websites like Google, Wikipedia, YouTube and more
• Encode special characters into HTML entities or URL links
• Calculate mathematical expressions
• Convert currencies and other units
• Sort lines, remove duplicates and remove blank lines
• Convert to lowercase, uppercase or title case
• Convert accented characters to plain ASCII text
• Convert Serbian text between Latin and Cyrillic alphabets
• Calculate MD5 and SHA1 checksums
• Execute terminal commands

These commands will replace the selected text in any Mac OS X application, just like magic. You don’t need to switch to a different program, or even copy and paste.

KavaServices is highly customizable. You can select which commands you'd like to appear in the Services menu, and you can add custom unit conversions and web searches.

Requirements:
OS X 10.6
Intel

Also available is:
Universal Binary version 3.2.2 for OS X 10.4 through 10.5