1) The first key phrase is “for the purpose of delivering the service.” In order to produce your calendar, put your photos on a CD, create an album, or make whatever product you’ve ordered, the company of course has to digitally reproduce, possibly edit and print your photo. Therefore, you’ll be required to legally grant the company the right to use your photo. You’re only giving the company the right to create the product you asked it to, nothing else.
2) You grant this right “non-exclusively”–meaning that you also can extend your rights to anyone or any other company you wish.
3) The statement “[you] warrant that you have a right to grant such a license” is also important: It’s an acknowledgment that you actually have the copyright or permission to use the photos you upload. This statement protects the company against legal action if a customer reproduces photographs illegally. For example, say you get your kid’s picture taken at Olan Mills, then you scan one of the photos and upload it to PhotoWorks so you can order a product. That’s a violation of copyright law, because professional photo studios almost always copyright their work (that way, you have to buy the photos from that studio). It would be impossible for PhotoWorks or any such site to vet all the photos its users upload. By PhotoWorks’ inclusion of this statement, Olan Mills (in this example) couldn’t sue PhotoWorks if PhotoWorks’ users were reproducing Olan Mills’ copyrighted photographs without the studios permission.
4) “Moral rights” has nothing to do with morality, but with the copyright holder’s right to attribution and to the integrity of the work (see http://en.wikipedia.org/wiki/Moral_rights). Again, in my not-legal opinion, by “waiving moral” rights, you’re waiving your right to have a “credit line” on a PhotoWorks products and allowing the company to “change” the image by affixing it to a coffee mug etc.