Hi!
Skim (skim-app.sourceforge.net), a very neat and free pdf-viewer supports now pdfsync and they set up a wiki with some instructions how to enable Skim as viewer for pdfsync in Textmate. But I think the instructions are more complex than they should be.
The site is: http://skim-app.sourceforge.net/wiki/index.php/ LaTeX_and_PDFSync
Isn't it even in the standard-install of TextMate only necessary to set the Shell Variable TM_LATEX_VIEWER to Skim?
Niels