Sure, Stanza will work with the iPod.
And, as far as I know, you can e-mail him non-DRM files and he'll be able to open them on the iPod. If he gets the Kindle app, he can open non-DRM'd mobi files. If he gets the Stanza app, or iBooks (or a bunch more), then he can open/use epub books. Oh, and PDFs will work fine too in Stanza.
If I may make a suggestion? [I am assuming you are not physically near your son...]
Sign up for a free Dropbox account (you get 2G of storage free). Then, you can create a public folder in which you can "drop" any book. Then, you can send your son the link to that folder and he'll be able to access it from his iPod's web browser and will be able to download any book you put in it. And, you can keep putting books in that folder and just tell your son they are there. Saves you e-mailing stuff and he'll be able to look at any book you place there at any time he wishes.
Can you tell I really like Dropbox?
Oh, and yes, a new iPod does come with a charger.
Hope this helps.
Marilyn
P.S. But I don't think libraries
have non-DRM books, do they?