Your excitement about reading can be the best thing to motivate your son.
My son was a late reader. I am an avid reader, so I was worrying a lot when he was around 8yrs old, especially when his friends could read and it started affecting his self-esteem ("How come they can all read and I can't?"). I did lots of phonics activities with him (we homeschool) which he grunbled a lot about, but I pressed on anyway. I continued to read to him constantly, and then as another person suggested, I slipped away when I needed to do some other things. My son couldn't stand being left "hanging" so little by little he continued on reading when I left. He would also see me reading on my own, so he would know it was something grownups did, not just something grownups told kids to go do.
Now 2 years later, my son is an avid reader. He's read through all of the Lord of the Rings, all of the Harry Potter books, all of the Edge Chronicles, and now we're working our way through books by Lloyd Alexander (just finished his series of Taran books). He has loved reading anything about Star Wars (especially the Star Wars Visual Dictionary). He also loved Madeline L'Engle.
I still read to him at bedtime, and he takes along a book when we go somewhere in the car. On the weekend I often don't see him for hours at a time, he'll be curled up with a book. He still asks me to read to him now and then, and I eagerly oblige! (Sometimes when I leave his room after bedtime reading, he'll see me grab our "bedtime book" on the way out so I can continue reading!)
I think what's also helped is finding books of interest to him. He likes science fiction, time travel, space, etc. He loves exploring the library (we frequent 3 different ones). Unless there's something truly objectionable, I let him take home whatever he likes.
Hope some of this helps, good luck!