Few days back my friend Mukesh was writing a e-book on affiliate marketing. The e-book was supposedly for the viral marketing, hence there were many affiliate links in it. He wrote the book in MS Word and converted it to PDF using Cute PDF convertor. When he tested the PDF document all the URLs were non functional. He found the same problem with many other PDF convertors.
Then last Sunday day he told me the problem and asked me if I knew any other method to convert the documents to PDF format. I suggested Adobe Acrobat Writer. But he told me that it was not possible for him to buy acrobat writer.
He did that and to his surprise his all affiliate links were functional in the PDF version of the e-book.
Therefore all you need is a Google email account. With this email account id then you can log on to the Google docs and create your own PDF documents with embedded URLs which are very much functional.