Monkeybread Software (
has released version 4.4 of the application, Combine PDFs. The
upgrade inludes bug fixes and a new preferences dialog.

Combine PDFs is a utility that allows you to merge a PDF and image
into one PDF file. You can split a PDF file or create a new PDF file
with interleaved pages from two different PDF files. Options are
available to apply Quartz Filters, add encryption and metadata.

Combine PDFs requires Mac OS X 10.3.9. It costs US$30, but version
4.4 is a free update for registered users of version 4.x.