pdf manipulation with RoR?

New to rails and I'm working on a site for ebooks and was wondering if
there are any plugins for rails that will allow me to generate pdfs on
the fly like safari books, where after you order a book it prepares a
pdf with your user name on each page.

Thankd for all the help.

No, there aren't, but you can use the pdfstamp.pl from Perl's Text::PDF to do it. That's what I use for my ebook on building e-commerce sites in Rails.

There are no plugins for rails, but you can use this library in your
app : http://ruby-pdf.rubyforge.org/