Release Notes:

New re-written version (now require Leopard)
You can pair pages (ex. 2 pdfs with not pair number of pages will be completed with two empty page after the last page of each one)
You can arrange files with a new interface (and see thumbs of pages live while you are working
New user interface with drag&drop support
Combine function now works better and faster
You can choose to import one or more pages from another pdfs without importing the entire file
Auto-update with Sparkle