Adding a text to every page of a PDF?

Acrobat does that, of course, but I guess you don't have Acrobat. I think there are free or cheap PDF-to-otherformat converters (to MS Word, for example). If you can convert to an editable format, you can make a header for the doc and then get a free http://www.pdfonline.com/.

Automator. Yup. It's a little tricky - you'd have to cheat and make it a watermark at 100%. I just built a watermark option (you'd create the text as a watermark, preferably as anything other than a PDF). You run this action and it'd watermark every page (at 100% opacity in your case) with the text. I built it for someone, so you're welcome to try it out. I just put the workflow on my http://hompage.mac.com/jeffgreenberg. one note - you'll need tiger + automator. You'll have to open the workflow, 'choose' your pdf (you'll see the action) and then adjust the scale/position. I think if you want it centered you're fine...if you want a left/right page difference it's a bit harder (you'd have to seperate the pages, do the left seperate from the right and rejoin). I'm not sure how easy/hard that is.

You can use http://www.iconus.ch/fabien/pdflab/ to add a watermark to every page of an existing PDF file. It supports a number of image formats for the watermark, including PDF. Simply create a single page PDF file with your text in the top left corner and then overlay it on every page of the existing PDF file (you may have to fiddle with how you generate the watermark PDF file in order to get the margins correct, since PDFLab will attempt to center the watermark). PDFLab is available for free, but the author accepts donations.

Thanks for all the suggestions. I ended up downloading the 30 day trial of Acrobat Professional. There's no trial version for Mac (wtf?) so I fired up an old version of VirtualPC and installed it. I was able to add the text easily and on resaving, the file compressed significantly to boot.