TeXlipse is a LaTeX plugin for Eclipse. The installation of both is assumed here.

To activate forward and inverse search on the Eclipse/TeXlipse side, in “Preferences/Texlipse/Viewer Settings”, add a new Viewer configuration in top priority, with the following viewer configuration:

• Viewer name: skim
• Ordered List ItemViewer command: /Applications/Skim.app/Contents/SharedSupport/displayline
• Viewer arguments: -r %line “%file” “%texfile”
• Viewer input file format: pdf
• Inverse search support: Viewer runs external command
• Viewer supports forward search: selected

Also make sure that the “-syntex=1” argument is added to the PdfLatex program in “Preferences/Texlipse/Builder Settings”.

On the Skim side, “Prefrences/Sync/PDF-Tex sync support” should be configured as follows:

• Preset: Custom
• Command: java
• Arguments: -classpath /Applications/Eclipse-3.6/plugins/net.sourceforge.texlipse_1.4.1/texlipse.jar net.sourceforge.texlipse.viewer.util.FileLocationClient -f %file -l %line

http://mactex-wiki.tug.org/wiki/index.php/SyncTeX#TeXlipse.2FSkim