Just to clarify.... You can get your son's internet signal in your house? This would make life somewhat easier but not necessary...
I think the two you want to look at are:
Kindle ($79 at Amazon): Basic reader. You can buy books from Amazon or your library. In order to turn pages or navigate from book to book, you have to click a button on the bottom of the device.
Kindle Touch ($99 from Amazon): This would be my recommendation between the 2. Navigate by touching the screen. Can play audio files (if he likes audio books) and VERY (and I mean
very) limited music capabilities if he likes to listen to music and read. Also 2GB more memory altho he probably doesn't need that much. For $20 more, the touch screen and audio book support is a nice feature
As an added bonus, on either reader, he can read PDF and Word documents if he likes.
With either device, you can get books via dial up by plugging the device into your computer via the USB cable that comes with the Reader. You can probably DL directly to the device OR put it on your PC then drag and drop it to the Kindle.
ETA: If you can get your son's internet signal at your house (and he doesn't mind) AND don't mind a $200 price tag, then I hands down recommend the Kindle Fire!! Why? Because YOU will not be able to put it down due to the web surfing
Actually, better budget $300 because after fighting over it, you'll still end up buying him the Kindle touch!! hehehe