As you may or may not know, I am something of a Mac hater. I think Apple blew it so badly with this whole OSX thing that the whole company should just be shot into space and forgotten. But I do use one on a daily basis at my place of employment for graphic arts work before the former graphic artist was a Mac person, and I ended up in their position (in addition to my other work. Whee!)
Recently, I wanted to print a document across multiple pages. Not a big deal, of course. A little quick googling turned up an excellent Freeware (as-in-beer) program called MindCAD Tiler. This is a snazzy little application for printing PDFs across multiple sheets. It's smart enough to know your printable area/margin (from the PPD) so it can properly break the print at the edge of the printable area.
What makes MindCAD Tiler special, aside from the fact that you don't have to pay for it, is that it has a very nice and simple interface. The interface doesn't allow you to easily scale the PDF to an arbitrary size, but it does allow you to put in a percentage value in the Page Setup dialog, and there's also a button to automatically stretch the document to the printable area. Unfortunately, this is based on the document size and not the size of the actual content, so you won't be able to use this button unless the image approaches the page margins.
In general, the program is quite easy to use. Generate a PDF, then load it into Tiler. There's buttons to add more pages of width or height, and to remove that width or height. There's a print button, the autoscale button, next and previous page buttons, and a button to toggle the page orientation (so you don't have to do it in the page setup.) All very nice. The only thing I'd ask for would be a field you can use to set scale by percentage in the toolbar.
In spite of this one drawback, this program is so good, I stopped looking when I found it.